USOO6541659B1 (12) United States Patent (10) Patent No.: US 6,541,659 B1 Chen (45) Date of Patent: Apr. 1, 2003

(54) PROCESS FORACYL SUBSTITUTION OF (56) References Cited ANHYDRIDE BY WANADYL SALT CATALYST PUBLICATIONS (75) Inventor: Chien-Tien Chen, Taipei (TW) Klaseketal, Chemical Papers, (1997) 51 (2) pp. 111-116 as described in Chemical Abstract vol. 127 num 135436. (73) ASSignee: National Taiwan Normal University, Lee et al, Bull. Korean Chem. Soc. (1988) 9 (6) pp. Taipei (TW) 362-364, as described in Chemical Abstract, Vol. 110, No. - 204627.* (*) Notice: Subject to any disclaimer, the term of this Chem Abrst. vol. 110, No. 204627 Lee et al.* patent is extended or adjusted under 35 Chem. Abst. vol. 127 No. 135436 Klasek et al. U.S.C. 154(b) by 0 days. C. AOS. WO. O. SCK C. a. * cited by examiner (21) Appl. No.: 10/115,546 Primary Examiner Alan L. Rotman Assistant Examiner Hector M Reyes

(22) Filed: Apr.a 2,49 2002 (74) Attorney, Agent, or Firm Morgan & Finnegan, LLP (57) ABSTRACT (51) Int. Cl." ...... C07C 69/02; B01J 21/00 A proceSS for acyl Substitution of an anhydride with an active-hydrogen-containing compound includes reacting the (52) U.S. Cl 560/231; 502/100: 502/103; anhydride with the active-hydrogen-containing compound in the presence of a Vanadyl Salt catalyst to obtain a high 502/151; 502/153; 502/154 yield of acyl Substitution reaction product with high chemoSelectivity. (58) Field of Search ...... 560/231; 502/100, 502/103, 151,153, 154 10 Claims, No Drawings US 6,541,659 B1 1 2 PROCESS FOR ACYL SUBSTITUTION OF SUMMARY OF THE INVENTION ANHYDRIDE BY WANADYL SALT CATALYST Therefore, the object of the present invention is to provide a process for acyl Substitution of an anhydride with an BACKGROUND OF THE INVENTION 5 active-hydrogen-containing compound that is devoid of the 1. Field of the Invention aforesaid drawbacks of the prior art. The invention relates to a proceSS for acyl Substitution of an anhydride with an active-hydrogen-containing Accordingly, the proceSS for acyl Substitution of an anhy compound, more particularly to a proceSS for acyl Substitu dride with an active-hydrogen-containing compound tion of an anhydride with an active-hydrogen-containing includes reacting the anhydride with the active-hydrogen compound in the presence of a Vanadyl Salt catalyst So as to containing compound in the presence of a Vanadyl Salt obtain a high yield of acyl Substitution reaction product with catalyst So as to obtain a high yield of acyl Substitution high chemoSelectivity. reaction product with high chemoSelectivity. 2. Description of the Related Art 15 The acylations of , amines and thiols are impor tant and commonly used transformations in organic Synthe DETAILED DESCRIPTION OF THE Sis. In these reactions, acid halides or anhydrides are often PREFERRED EMBODIMENTS employed as the acyl Source in basic media or in the presence of Lewis base or acid catalysts. In the past, trimethylsilyl (TMS) and metal triflates, such as indium, In the process according to this invention, the anhydride Scandium, copper, and bismuth triflates, have been found to is reacted with the active-hydrogen-containing compound in be effective in catalyzing the acylation of alcohols with the presence of a Vanadyl Salt catalyst. anhydrides. However, only a few of them have been studied with more extensive Species of anhydrides, and Substrates 25 The vanadyl salt catalyst has the following formula: bearing acid-Sensitive groups, Such as acetonide and allyl, might not be fully compatible. Moreover, most of these catalysts have encountered Some disadvantages. For example, the acylation of allyl alcohols (Such as cinnamyl (VO)X, ) catalyzed by Scandium triflate would produce rear ranged by-products. The acylation catalyzed by trimethyl wherein X is selected from the group consisting of (OTf), silyl triflate should be operated at a temperature of O C. or SO-aryl, SO, (acac), (CH-CO), (F), (Cl), (Br), (I), less So as to Suppress the hydrolysis of the functional groups Al-O, (N), SbF6, HPO, MoC), (NbO), (NO), CO, on the Substrates. In addition, the actual role of the afore (CIO), SeO, Pt(CN), TiO, WO, and ZrO. mentioned catalysts in the catalytic pathway was not fully 35 understood. In this application triflate refers to trifluo The active-hydrogen-containing compound has the fol romethaneSulfonate. lowing formula: Notably, the preparation of metal triflates often require direct mixing of metal oxides with excess hot triflic acid (trifluoromethane sulfonic acid). The unavailability of com 40 plete removal of triflic acid from the metal triflates will diminish the value of the metal triflate as a catalyst because wherein it might affect the overall catalytic activity in the acylation process. In this context, new mild and neutral catalysts, Y is selected from the group consisting of O, NH and S; which can achieve general nucleophilic acyl Substitution of 45 R is hydrocarbylene group; anhydrides with protic nucleophiles, remain in great each of R is independently selected from the group demand. consisting of moiety, ester moiety, lactone The value of -containing compounds as a cata moiety, ketone moiety, imide moiety, acetonide moiety, lyst in Synthesis has been widely Studied and assessed. and lactol moiety; Among them, oxovanadium (IV) (vanadyl) compounds were 50 normally treated as pre-catalysts of the corresponding Vana m is 0, 1, 2 or 3; dium (V) species. However, Synthetic reactions and path n is 0, 1, 2, or 3; and ways that are directly catalyzed by Vanadyl species were m+n=3 rarely Studied in contrast. Togni in organometallics, 1990 “OTf represents triflate or trifluoromethane sulfonate. reported the use of camphor-derived vanadyl bis (1,3- 55 diketonato) complexes as Lewis acid catalysts for asymmet The anhydride typically has the following formula: ric Diels-Alder reactions between Danishefsky dienes and aldehydes. Although a concerted pathway was Suggested in the report, the potential amphoteric characteristic of the V=O unit (i.e., "V-O) which could...be conducive to a 60 Stepwise, push-pull type mechanism was not taught. wherein each of R is independently selected from the Namely, the (partial) positively charged V in the V=O unit group consisting of acyclic aliphatic moiety, cyclic is a Lewis acid which is Sufficient to activate the carbonyl aliphatic moiety and aromatic moiety. oxygen of an aldehyde. In the meantime, the (partial) A proposed reaction mechanism between an amphoteric negatively charged O in the V=O unit serves as a Lewis 65 Vanadyl Salt catalyst and an anhydride in the catalytic base to activate an enol Silane and to permit dissociation of acylation of an alcohol is illustrated in the following the Silyl group concomitantly. Scheme 1: US 6,541,659 B1 4 Example 3 Scheme 1: C(O)R’ The Preparation of Vanadyl Chloride IV(O)Cl.-X O O o1 XSY X-Y, RC(O)IO ^ (HO) x1 x1 x1 YOC(OR In a dry 5-mL, two-necked, round-bottomed reaction flask, vanadylsulfate trihydrate (114.0 mg, 0.53 mmol) was placed, followed by addition of aqueous methanol (MeOH/ HO, 1/0.3 mL). A solution of BaCl-2H2O (122.1 mg, 0.50 O mmol) in methanol (1 mL) was added to the reaction flask L/N-K 9i us R at ambient temperature. After 30 min of Stirring, precipita R o1 tion of bariumsulfate was observed, which was filtered off over a short pad of dry Celite. The filtrate was concentrated and dried in vacuo at 120° C. for 4 hours, and 86.4 mg (90% yield) of Vanadyl chloride as pale purple Solids was obtained. AS shown in the above Scheme 1, a protic nucleophile Example 4 (e.g., the alcohol in the Scheme) may add to one of the two alkanoates in the adduct with concomitant elimination of an alkanoic acid to regenerate the Vanadyl Salt catalyst. The Preparation of Vanadyl Azide IV(O) (N)-X The most preferred Vanadyl triflate catalyst can be pro (HO) duced either by reacting vanadylsulfate with barium triflate In a dry 5-mL, two-necked, round-bottomed reaction or by reacting Vanadium oxide and an excess of triflic acid 25 in a Suitable Solvent. flask, vanadylsulfate trihydrate (114.0 mg, 0.53 mmol) was The process according this invention is useful for the placed, followed by addition of methanol (1 mL). A solution acylation required in the proceSS for preparing Sun-Screen of Ba(N) (112.5 mg, 0.51 mmol) in methanol (1 mL) was lotion and Surfactant, Such as the acylation of Sorbitol, added to the reaction flask at ambient temperature. After 30 glycerin, fatty acid or N,N-dimethyl benzoic acid. The min of Stirring, precipitation of barium Sulfate was observed, process according to this invention is also useful for the which was filtered off over a short pad of dry Celite. The acylation of Saccharides and the Synthesis of peptides. filtrate was concentrated and dried in vacuo at 120° C. for 2 The following examples further illustrate the preferred hours, and 91.5 mg (88% yield) of vanadyl azide as brown embodiments of the invention, but are not to be construed as ish Solids was obtained. limiting. 35 EXAMPLES: Example 5 Example 1 The Preparation of Vanadyl Hexafluoroantimonate V(O) (SbF)-x(HO) The Preparation of Vanadyl Triflate V(O) (OTf)-x 40 (HO) In a dry 5-mL, two-necked, round-bottomed reaction (V(O)SO3HO) (342 mg, 2.1 mmole) flask, vanadyl chloride trihydrate (88.0 mg, 0.50 mmol) was was added into a two-neck flask (50 ml, Vacuum-dried), and placed, followed by addition of THF (2 mL). A solution of is then dissolved with methanol (2 ml). Barium triflate AgSbF (343.5 mg, 1.0 mmol) in THF (1 mL) was added to solution in methanol (2M, 2 ml) was added at room tem 45 the reaction flask at ambient temperature. After 2 hours of perature and mixed homogeneously for 30 mins. Barium Stirring, precipitation of Silver chloride was observed, which Sulfate precipitate was formed. The precipitate was filtered was filtered off over a short pad of dry Celite. The filtrate Via diatomaceous earth, and the filtrate was-collected. The was concentrated and dried in-vacuo at 120° C. for 4 hours, Solvent remained in the filtrate was removed under vacuum 50 and 254.6 mg (86% yield) of vanadylhexafluoroantimonate (120° C., 4 hrs). Dark blue solid (622 mg, yield: 85%) was as redish brown Solids was obtained. obtained. The obtained vanadyl triflate can be used directly for the acylation. Example 6 Example 2 The Preparation of Vanadyl Acetate IV(O) (OAc)- 55 The Preparation of Vanadyl Perchlorate V(O) x(HO) (CIO)-x(HO) In a dry 5-mL, two-necked, round-bottomed reaction In a dry 5-mL, two-necked, round-bottomed reaction flask, vanadylsulfate trihydrate (114.0 mg, 0.53 mmol) was flask, vanadyl sulfate trihydrate (114.0mg, 0.53 mmol) was placed, followed by addition of methanol (1 mL). A solution 60 placed, followed by addition of methanol (1 mL). A solution of Ba(OAc) (130.3 mg, 0.51 mmol) in methanol (1 mL) of Ba(CIO) (171.5 mg, 0.51 mmol) in methanol (1 mL) was added to the reaction flask at ambient temperature. After was added to the reaction flask at ambient temperature. After 30 min of Stirring, precipitation of barium Sulfate was 30 min of Stirring, precipitation of barium Sulfate was observed, which was filtered off over a short pad of dry observed, which was filtered off over a short pad of dry Celite. The filtrate was concentrated and dried in vacuo at 65 Celite. The filtrate was concentrated and dried in vacuo at 120° C. for 4 hours, and 109.5 mg (90% yield) of vanadyl 120° C. for 2 hours, and 130.6 mg (80% yield) of vanadyl acetate as bluish Solids was obtained. perchlorate as brownish Solids was obtained. US 6,541,659 B1 S 6 Example 7 ambient temperature. After about 10 min, a Solution of 2-phenylethanol (122 mg, 119.3 ul, 1.0 mmol) in CHCl (2 The Preparation of Vanadyl Tetracyanoplatinate IV mL) was slowly added to the above brownish solution, and (O)Pt(CN)-x(HO) the reaction mixture was stirred for 7.5 hours. After comple In a dry 5-mL, two-necked, round-bottomed reaction tion of the reaction as monitored by TLC, the reaction flask, vanadylsulfate trihydrate (114.0 mg, 0.53 mmol) was mixture was quenched with cold, Saturated aqueous placed, followed by addition of methanol (1 mL). A solution NaHCO Solution (5 mL). The resulting separated organic of BaPt(CN)4-xH2O (222.5 mg, 0.51 mmol) in methanol (1 layer was washed with brine, dried (MgSO), filtered, and mL) was added to the reaction flask at ambient temperature. evaporated. The crude product was purified by column After 30 min of Stirring, precipitation of barium Sulfate was chromatography on Silica gel to yield 154.2 mg of observed, which was filtered off over a short pad of dry 2-phenethyl acetate (94%) as colorless oil. The substrate, Celite. The filtrate was concentrated and dried in vacuo at reaction time, and yield of this test are Summarized in Entry 120° C. for 4 hours, and 190.8 mg (89% yield) of vanadyl 2 of the following Table 1. tetracyanoplatinate as brownish Solids was obtained. 15 Entry 3 Example 8 Acetylation Reaction with Vanadyl Sulfate In a dry 50-mL, two-necked, round-bottomed flask, The Preparation of Vanadyl Titanate IV(O)TiO-X vanadyl sulfate (8.2 mg, 0.05 mmol) in 3 mL of anhydrous (HO) CHCN was placed. To the above mixture, In a dry 5-mL, two-necked, round-bottomed reaction (153.1 mg, 141.5 ul, 1.5 mmol) was slowly added at flask, vanadylsulfate trihydrate (114.0 mg, 0.53 mmol) was ambient temperature. After about 10 min, a Solution of placed, followed by addition of methanol (1 mL). A solution 2-phenylethanol (122 mg, 119.3 uL, 1.0 mmol) in CHCN (2 of BaTiO (118.9 mg, 0.51 mmol) in methanol (1 mL) was mL) was slowly added to the above bluish solution with added to the reaction flask at ambient temperature. After 30 25 residual Suspended Vanadyl Sulfate, and the reaction mixture min of Stirring, precipitation of barium Sulfate was observed, was stirred for 24 hours. After completion of the reaction as which was filtered off over a short pad of dry Celite. The monitored by TLC, the reaction mixture was quenched with filtrate was concentrated and dried in vacuo at 120° C. for 4 cold, saturated aqueous NaHCO solution (5 mL). The hours, and 101.9 mg (92% yield) of vanadyl titanate as resulting Separated organic layer was washed with brine, bluish Solids was obtained. dried (MgSO), filtered, and evaporated. The crude product was purified by column chromatography on Silica gel to Example 9 yield 150.9 mg of 2-phenethyl acetate (92%) as colorless oil. The Substrate, reaction time, and yield of this test are Acetylation Reaction of Vanadyl Salt Catalysts summarized in Entry 3 of the following Table 1. In this example, four different Species of Vanadyl Salt 35 Entry 4 catalysts were tested in mediating the acetylation of 2-phenylethanol. Acetylation Reaction with Vanadyl Triflate Entry 1 Vanadyl triflate was first heated in refluxing trifluoroacetic 40 anhydride (R'=CF) for 12 hours and then concentrated. The Acetylation Reaction with Vanadyl Acetylacetonate resultant adduct was treated with a Stoichiometric amount of 2-phenylethanol in CHCl for 3 hours. The corresponding In a dry 50-mL, two-necked, round-bottomed flask, 2-phenethyl trifluoroacetate was isolated. The Substrate, vanadyl acetylacetonate (13.7 mg, 0.05 mmol) in 3 mL of reaction time, and yield of this test are Summarized in Entry anhydrous CH2Cl was placed. To the above Solution, acetic 45 6 of the following Table 1. anhydride (153.1 mg, 141.5 uL, 1.5 mmol) was slowly The Substrates, reaction times, and yields of the test of added at ambient temperature. After about 10 min, a Solution other entries are summarized in the following Table 1. of 2-phenylethanol (122 mg, 119.3 uL, 1.0 mmol) in CHCl (2 mL) was slowly added to the above dark green Solution, TABLE 1. and the reaction mixture was stirred for 5 hours. After 50 completion of the reaction as monitored by TLC, the reac Catalytic Acylations of 2-Phenylethanol tion mixture was quenched with cold, Saturated aqueous with Various Anhydrides in the Presence of Various NaHCO Solution (5 mL). The resulting separated organic Species of Vanadyl Salt Catalysts layer was washed with brine, dried (MgSO), filtered, and OH -- Ph evaporated. The crude product was purified by column 55 chromatography on Silica gel to yield 139.4 mg of O O 2-phenethyl acetate (85%) as colorless oil. The substrate, 1 mol% reaction time, and yield of this test are Summarized in Entry HeV(O)L 1 of the following Table 1. R O R CHCl2 Entry 2 60 Ph N1 Noctor Acetylation Reaction with Vanadyl Chloride Anhydride time In a dry 50-mL, two-necked, round-bottomed flask, Entry V(OL (R') (h) Yield, 7% vanadyl chloride (1.9 mg, 0.01 mmol) in 3 mL of anhydrous 65 1. V(O)(acac). CH 5 85 CH2Cl was placed. To the above Solution, acetic anhydride 2 V(O)Cl. CH, 7.5 94 (153.1 mg, 141.5 uL, 1.5 mmol) was slowly added at US 6,541,659 B1 7 8

TABLE 1-continued TABLE 2 Catalytic Acylations of 2-Phenylethanol Vanadyl Triflate-Catalyzed Acetylation and with Various Anhydrides in the Presence of Various Pivalation of Alcohols, Amines, and Thiols Species of Vanadyl Salt Catalysts O O 3 V(O)SOed CH, 24 92 4 V(O)(OTf), CH 0.5 98 V(O)(OTf)2 o us ls He1 mol% 5 V(O)(OTf). CH, O.75 98 R-XH + O R CHCl2 6 V(O)(OTf), CF, 3 98 7 V(O)(OTf), -Pr 1. 98 R = Me, C(CH3)3 8 V(O)(OTf), tert-Bu 11 99 9 V(O)(OTf), tert-BuO 28 95 O 1O V(O)(OTf), Ph 26 92 11 V(O)(OTf), Succinic 42 93 12 V(O)(OTf), phthalic 96 75g R Yx ls R 15 "Isolated yields. Entry substrate time, h yield, 7% Acetylacetonate. Five mol % catalyst was used. 1. Ph(CH)OH 0.5 (11) 99 (99) The trihydrate was used. 2 PhCH=CHCH-OH 3.5d (72e) 98 (85) CHCN was used as solvent. Catalyst was recovered from aqueous layer and reused for 5 consecutive 3 10 (24) 97 (97) S. 8Diphenethyl ester was isolated in 16%.

Trials with 5 mol % of vanadyl acetylacetonate 4 1 (96) 97 (84) (VO(acac)) and Vanadyl Sulfate were effective to complete the acetylation at ambient temperature in the presence of 1.5 25 equiv. of AcO in 5 and 24 hours, respectively. Vanadyl chloride and triflate, which were prepared from vanadyl sulfate and suitable barium salts, were found to be 5 1 (58) 98 (95) much more reactive. Acetylation using 1 mol% of V(O)Cl. and V(O) (OTf) with 1.5 equiv. of AcO in CHCl was completed in 7.5 and 0.5 hours, respectively, leading to phenethyl acetate with at least 94% yield. It should be noted that the corresponding VC1 and V(OTf) are catalytically 35 inactive, Supporting the role of the V=O unit in the vanadyl 6 5 (36) 99 (99) catalysts. In addition, there is no need for chromatographic purification with the acetylation protocol Since the remain ing acetic anhydride and Vanadyl triflate can be readily removed by direct aqueous wash. More importantly, V(O) 40 (OTf) is fully compatible with water. It can be recovered 7 8 (42) 99 (99) from the concentrate of the aqueous layer and reused for at least five consecutive runs with Similar catalytic activity. AS shown in Table 1, besides acetic anhydride, the cata 45 lytic System is amenable to acyclic, cyclic, aliphatic and 8 40 (96) 99 (98) aromatic anhydrides. In general, the more hindered the anhydride, the slower the acylation rate. (i.e., CH->i-Prst Bu; refer to entries 4, 7 and 8 in Table 1). Acylation with an aromatic anhydride (e.g., R-Ph in entry 10 of Table 1) is up 50 9 (i-Pr).NH 3 97 to 50 times slower than those with aliphatic anhydrides 1O tert-BuSH 12 (24) 99 (95) (entries 4 and 6-8 in Table 1). Acylation with di-tert-butyl 1.5 equiv of anhydride was used unless otherwise stated. dicarbonate also proceeds well and with a rate Similar to that Isolated yields and characterized spectroscopically. of benzoylation (entry 9 in Table 1). Cyclic anhydrides, such The data in parentheses correspond to pivalations. 55 Two equiv of anhydride was used. as Succinic and phthalic anhydride, are the least reactive Three equiv of anhydride was used. (entries 11 and 12 in Table 1). THF was used as solvent. Toluene was used as solvent. Example 10 In almost all cases, except in the pivalations of cinnamyl 60 alcohol (85%) and menthol (84%), the chemical yields of With the optimal catalyst-Vanadyl triflate on hand, nucleo acylation were at least 95%. In general, acetylations proceed philic acyl Substitutions of both acetic and pivalic anhydride much faster than the corresponding pivalations. Acylations (representing two steric extremes) with protic nucleophiles go Smoothly with primary, Secondary, and acid-Sensitive (e.g., alcohols, amines, and thiols) of varying Steric and allylic and benzylic alcohols. No trace of allylic or pinacol electron transfer demands were tested in this example. The 65 rearrangement by-products was observed in the case of Substrates, reaction times, and yields of the test in this cinnamyl alcohol and 10,11-dihydroxy-dibenzoSuberane example are Summarized in the following Table 2. (entries 2 and 5 in Table 2). Tertiary alcohols, such as US 6,541,659 B1 9 10 tert-butyl alcohol and trityl alcohol, were inactive. Example 11 Nevertheless, the corresponding tert-butanethiol was fairly reactive (entry 10 in Table 2). Aromatic alcohols, amines and Acetylation and/or pivalation of various functionalized thiols (e.g., 2-hydroxy, 2-amino, and 2-thio-naphthalenes) Substrates were tested in this example. The Substrates, reac were amenable to acylations in essentially quantitative 5 tion times and yields of the test in this example are Sum yields (entries 6-8 in Table 2). marized in the following Table 3.

TABLE 3 Acetylation and/or Pivalation of Functionalized Substrates Entry substrate time, h yield, 7% OH 0.5 (48) 99 (99)

2 (3) 96 (95)

0.5d (1.5) 100 (85)

12 (24) 95 (95)

6 (12) 100 (100)

90

75

85 OH

HO HO OH US 6,541,659 B1 11 12

TABLE 3-continued Acetylation and/or Pivalation of Functionalized Substrates Entry substrate time, h yield, 7% 9 f-cyclodextrin 968 90 1O : 3 (48) 95 (96) OH

OH 11 t-Bu 2hi (15) 60 (97)

HN : OH

1.5 equiv of anhydride was used unless otherwise stated. 'Isolated yields and characterized spectroscopically. The data in parentheses correspond to pivalations. Two equiv of anhydride was used. Three equiv of anhydride was used. 'Carried out at -5°C. No solvent was used. "Asterisk signifies the reactive site. For effective mono-acylation, 0.95 equiv of anhydride was used. Di-acetylated product was isolated 10% yield.

As shown in Table 3, the acylation protocol is tolerant to treated with a mixture of oleic acid and benzoic anhyride protic nucleophiles bearing functional groups, Such as (1.1 equiv.) in CHCl with 5 mol % of vanadyl triflate for alkene, ester, lactone, ketone, imide, acetonide and lactol 2 hours. The resultant oleate was produced smoothly with (entries 1-9 in Table 3). Their acylations proceeded 82% yield. The mixed anhydride technique can also be smoothly with 75-100% yields. Side reactions, such as applied to dipeptide Synthesis, as illustrated in the direct oxidation (dehydrogenation) and dehydration, were not coupling of Fmoc-L-leucine and methyl t-tert-leucinate with observed in the case of C-hydroxy, C.-amino esters (entries 93% yield. 2 and 3 in Table 3), and B-hydroxy esters and ketones 35 (entries 4 and 5 in Table 3). No trace of the glycosidic C-O Scheme 2 cleavage was observed in the acetylation of diacetone-D- Acylations with Mixed-Anhydride glucose (entry7 in Table 7) at -5° C., although 22% of Aproaches in Oleate and Dipeptide Syntheses acetylation at the primary with concomitant OH 5 mol% migration of the acetonide-unit could not be prevented. 40 The high catalytic efficacy of vanadyl triflate was further ~~ (PhC(O))2OV(O)(OTf)2 demonstrated in the peracetylations of polyhydroxyl Ph N + oleic acid cHo, molecules, Such as uridine, lactose, and cylcodextrin (21 OH groups). In all cases, reactions go to completion in acetic 45 acid or in neat acetic anhydride, albeit with longer reaction ~~~ time (2.5–4 days). By taking advantage of the differential reactivity between nucleophiles, chemoSelective acylation of 3-hydromethyl-2-naphthol could be carried out. Its pri tert-Bu O O mary hydoxyl group is acylated with complete chemoselec 50 tivity and with at least 95% yield (entry 10 in Table 3). Acetylation of tert-leucinol at the Sterically hindered amino -- 93% moiety was moderately Selective. The corresponding NH2 OCH3 FmocNH OH N-acetylated product was furnished with 60% yield. Nevertheless, the analogous N-pivalation proceeded with 55 S complete selectivity (97%). Example 12 HN NHFmoc Since benzoic anhydride is the least reactive acyclic ls anhydride, one may carry out acylation directly with fatty 60 tert-Bu COMe acid in the presence of benzoic anhydride. In this example, the in-situ-generated mixed anhydride acts as the real acylation reagent. The reaction of Example 13 1-phenethyl-3-buten-1-ol with a mixture of oleic acid and It was found that amines, thiols, and primary and aromatic benzoic anhyride and, the reaction of Fmoc-L-leucine with 65 alcohols are amenable to benzoylations. However, benzoy methyl t-tert-leucinate are shown in the following Scheme 2. lations of Secondary alcohols are rather limited and require As shown in the Scheme 2, 1-phenethyl-3-buten-1-ol was harsher reaction conditions. The Substrates, reaction times US 6,541,659 B1 13 14 and yields of the test for the benzoylation of alcohols, hours. The corresponding 2-phenethyl trifluoroacetate was amines and thiols are Summarized in the following Table 4. isolated with 87% yield. As shown in Table 4, the only workable secondary alcohol is shown in entry 8 of Table 4, which underwent benzoyla tion at 50° C. with 52% yield. V. TABLE 4 Tro1 YOC(O)CF, Benzowlation of alcohols, amines and thiols Entry Substrate Time, h yield, 7% 1O 1. Ph(CH)OH 26 92 In view of the aforesaid, the Vanadyl catalyst has been demonstrated to exhibit amphoteric catalytic behavior in 2 8O 99 nucleophilic acyl Substitutions with various anhydrides, and thus represents a new type of water-tolerant metal Salt 15 catalyst. The acylation protocol allows for chemoSelective OH acylation and tolerates many Structural and Substrate varia tions. Mixed anhydride technique allows for acylations with commercially unavailable anhydrides. While the present invention has been described in con 3 C 96 99 nection with what is considered the most practical and preferred embodiments, it is understood that this invention OH is not limited to the disclosed embodiments but is intended to cover various arrangements included within the Spirit and 25 Scope of the broadest interpretation So as to encompass all 4 C C 96 99 Such modifications and equivalent arrangements. I claim: NH2 1. A proceSS for acyl Substitution of an anhydride with an active-hydrogen-containing compound, comprising reacting 5 (i-Pr).NH 18 95 Said anhydride with Said active-hydrogen-containing com pound in the presence of a Vanadyl Salt catalyst, wherein Said 6 C C 96 96 Vanadyl Salt catalyst has the following formula: SH (VO)X, 7 Tert-BuSH 36 97 35 wherein X is selected from the group consisting of (OTf), SO-aryl, SO, (acac), (CH-CO), (F), (Cl), (Br), (I), 8 OH 72c 52 Al-O, (N), SbF, HPO, MoC), (NbO), (NO), CO, (CIO), SeO, Pt(CN), TiO, WO, and ZrOs. 2. The process as claimed in claim 1, wherein Said *OC(OPh 40 active-hydrogen-containing compound has the following formula: 9 t-Bu O 0.5 1OO

wherein HN OMe 45 1O : 60 83 Y is selected from the group consisting of O, NH and S; OH R is hydrocarbylene group; each of R is independently selected from the group OH consisting of alkene moiety, ester moiety, lactone 50 moiety, ketone moiety, imide moiety, acetonide moiety, 11 t-Bu 6de 73 and lactol moiety; m is 0, 1, 2 or 3; H.N. OH n is 0, 1, 2, or 3; and 55 m+n=3. 1.5 equiv of anhydride was used unless otherwise stated. 3. The process as claimed in claim 1, wherein Said 'Isolated yields and characterized spectroscopically. anhydride has following formula: Carried out in THF at 50° C. and with 2 mol % catalyst. Asterisk signifies the reactive site. For effective mono-acylation, 0.95 equiv of anhydride was used. 60 wherein each of R is independently Selected from the group consisting of acyclic aliphatic moiety, cyclic aliphatic moi Example 14 ety and aromatic moiety. To Support the mechanistic proposal shown in aforesaid 4. The process as claimed in claim 1, wherein Said Scheme I, vanadyl triflate was first heated in refluxing reacting Step is performed in the presence of methylene trifluoroacetic anhydride (R'=CF) for 12 hours and then 65 chloride. concentrated. The resultant adduct was treated with a sto 5. The process as claimed in claim 1, wherein Said ichiometric amount of 2-phenylethanol in CHCl for 3 Vanadyl Salt catalyst is vanadyl triflate. US 6,541,659 B1 15 16 6. The process as claimed in claim 5, wherein Said consisting of Sorbitol, glycerin, fatty acid, and N,N- Vanadyl triflate is produced by reacting Vanadyl Sulfate with dimethylbenzoic acid. barium triflate. 9. The process as claimed in claim 1, wherein Said process 7. The process as claimed in claim 5, wherein said is an acylation of Saccharide. Vanadyl triflate is produced by reacting Vanadium oxide and 5 10. The process as claimed in claim 1, wherein said an exceSS of triflic acid. process is a Synthesis of peptide. 8. The proceSS as claimed in claim 1, wherein Said proceSS is an acylation of at least one Selected from the group k . . . .