'•'ADDITION PRODUCTS FROM THE REACTION OF PHOSPHORUS (III) HALIDES WITH CARBONYL COMPOUNDS" By K.L. Freeman, B.Sc. This Thesis is submitted in fulfilment of the requirements for the degree of Master of Science. .Supervisor : Dr. M.G. Gallaoher, Department of Orqanic Chemistry, School of Chemistry, University of N.S.W. PREFACE The work described in this thesis was carried out in the Oroanic Chemistry Laboratories at the University of New South Wales from May 1964 to December 1967, under the supervision of Dr. M.J. Gallagher. It is original except in those parts so indicated. Part of the dissertation (Section i) has been oublished in a condensed form in Tetrahedron Letters and in the Australian Journal of Chemistry under the title "The Aluminium Chloride Catalysed Reactions of Phosphorus (ill) Halides and Carbonyl Compounds". Sections 2 and 3 have been published in the Australian Journal of Chemistry under the titles "The Alkaline Fusion of Phosphinic Acids" and "The Reactions of Tervalent Phosphorus Compounds with Dichlorodiphenylmethane". This thesis has not been submitted for a higher degree at any other University. l-'l'ik’ TABLE OF CONTENTS PAGE‘NO. SUMMARY - 1 Section 1 Aluminium Chloride Catalysed Reaction of Phosphorus (ill) Halides and Carbonyl Compounds. Introduction 2 Results and Discussion 4 Experimental Section. 25 Section 2 Alkaline Degradation of Phosphinic Acids. Introduction 43 Results and Discussion 45 Experimental Section 48' Section 3 Reaction of Phosphorus (ill) Compounds with Dichlorodiphenylmethane. Introduction 52 Results and Discussion 56 Exoerimental Section 65 Section 4 Attempted Preparation of 10-Phenylphos- phacridone. Introduction 72 Results and Dicussion 76 Experimental Section «2 TABLE OF CONTENTS PAGE NO References: 90 Acknowledgements: 96 SUMMARY The reactions of phosphorus (ill) halides and carbonyl compounds catalysed by partially hydrated aluminium chloride has been studied. It was found that both dichlorophenylphosphine and chlorodiphenylphosphine react with benzophenone to give chlorophenyl- methylphenylphosphinic chloride and benzhydryldiphenylphosphine oxide, respectively. Dichlorophenylphosohine, catalysed by aluminium chloride acted as a deoxygenating agent with phthalic anhydride to give another route to the preparation of biphthalyl. The reaction of phosphorus (ill) halides and alkyl ketones with aluminium chloride catalyst was complicated by the reaction of aluminium chloride and the ketone. A novel phenyl migration was obtained where benzophenone and dichlorophenyl phosphine reacted under certain conditions to give triphenylmethylphenyl- phosphinic chloride. The alkaline fusion of some phosnhinic acids and \ acid chlorides is'described. The degradation of complex phosphinic acids to yield easily isolated products proved useful in structure determination of the original acids. The site of attack of-phosphines on haloq^n com­ pounds has been investigated by-reacting a series of phosphines, qraded in order of increasing nucleophilicity with dichlorodiphenyl methane. 2. SECTION 1. The Aluminium Chloride Catalysed Reaction of Phosphorus ^IIl) Halides and Carbonyl Compounds, INTRODUCTION : The investigation of the reactions of phosphorus (TIT) halides and carbonyl compounds in the presence of aluminium chlor­ ide. in particular the reaction of benzonhenone and dichlorophenyl- phosohino, arose when this reaction was studied as a route to the synthesis of substituted 10-phenylphosohacridone heterocylics (see Section 4). 22 It has been reported that phosphorus trichloride and bepzophenone do not react in the presence of aluminium chloride. 2 although Conant etaj., have studied the uncatalysed reaction of saturated aldehydes and ketones and found, in general, that thet£-hydroxy ohos- phonic acids were formed. With benzonhenone, under forcing conditions 23 and in the presence of benzoic acid they obtained moderate yields of diphenylhydroxymothylphosphonic acid and low yields of another acid to which they were unable to assign a structure. Ph2C0 + PC13 Ph2C(OH)P(O)(0H}2 In Conant*s study there was no attempt to isolate the acid chloride and the reaction mixture was hydrolysed to the free acid. Kabochrif and 24 Sheleva , in a similar reaction were able to isolate the acid chloride when they reacted benzaldehyde and excess phosphorus trichloride. 3. 3cid ch1''nde obtefn^d as a ]ow mp-1 fdno sol'd was *~honv]chloronethylphos-» phonic dichloride in 62% yields. Ph C(0)H r5Cl_/ex'i ~ > PhCH(Cl)p(0)Clo An interest?no reaction of benzophenone has b^en described by darie ' '' who in 1903 reacted benzophenone with excess hynoohosphorous acid for several days at 100°. The acid v/hich was formed was assion^d the structure o Ph2C(0H)P(0H)2. With alkyl ketones the reaction with phosphorus (JTT) ha]-ides in the presence of aluminium chloride is complicated by the ability of aluminium chloride to initiate aldol-type condensations The resulting -=>c;p-unsaturated ketone is able then to react with the phosphorus (III) halide. A typical example is the reaction of acetone 26, 27. ’ with phosphorus trichloride in the presence of aluminium chloride to produce 2-raethylpentan-2-one-4-nhosphonic acid, and the reaction of 9P, dichl-orophenylphosphine and chalcone ‘ . The species formed when benzophenone and aluminium ch.lor- og ide react have been investigated and Menshutkin ‘ has been able to isolate a 1:1 mole adduct of m.n.l30(. For this reason two moles aluminium chloride were used in the initial attempt, to r-re --re lO-r-bo-v? • phoschacridone from benzophenone and dichlorophenylphospMne. 4. RESUITSJWD DTSCUSSIOU : Benzophonone was reacted with excess dichloroohenylnhos- phine catalysed by "moist" aluminium chloride (lumps which had been exposed in a loosely stopoered bottle tor 24 hours when a nett increase in weight of ca 4% had occurred). The reaction was carried out under nitrooen for 3 hours at 100°. The neutral fraction was obtained by pourinq the crude reaction mixture into excess, cold sodium hydroxide solution and extracting with benzene. A number of experiments were conducted where the ratios of benzophenone and "moist" aluminium chloride were varied. A maximum yield (66%) of chlorodiphenylmethylphenylphos- phinic chloride (l) was obtained when 1 mole of benzophenone, 2 moles of "moist" aluminium chloride and excess (4 mole) of dichloronhenylphosrhine were used. (See Table l). Under identical conditions nhosohorus trichloride and benzophenone could not be induced to react and benzophenone was recovered in high yields from the reaction mixture. Recovery of benzophenone in high yields also occurred when 1 mole of benzochonone an^ excess dichloro- ohenylphosphine were used or when 4 moles of "moist" aluminium chloride. 1 mole of benzophenone and excess dichloronbenylnhosphine wr' ••-eacted. A decrease in the yield of acid chloride (l) was noted ? moles ~ anhydrous aluminium chloride, 1 mole of benzoohenone and excess .os' - '-r were used. Assioning a structure to the neutral reaction product from the reaction of dichlorophenylnhosphine and benzophonone ca ta h : 5. \.ii.n two moles of "moist" aluminium chloride proved difficult. "he white crystalline produce, n.o.103-104°, obtained by pouring the reaction mixture into excess aqueous alkali and extractino with benzene oave an analysis that corresponded to a 1:1 adduct of benzophenone and the rhosphine. The product was able to be successfully recryst­ allized from ethanol and only reacted sluggishly with alcoholic silver nitrate. This evidence tended to rule out the possibility that the product was an acid chloride, although it was difficult to otherwise -lace two chlorine atoms in the molecule. The infrared spectrum showed a strong (d-0j stretch band and its proton magnetic resonance spec;.rum demonstrated that only aromatic protons were present. Fusion of the product (l) with solid sodium hydroxide (s*e Section 2) produced benzophenone as the only neutral product (57*0 and the acid fraction yielded benzhydrylphenylphosphinic acid (VI, 39.90. phenylphosnbmic acid (18x0 and traces of phenylphosnhonic acid. On this evidence the most likely assumption was that toe product, was chlorodiphenylmethylphenylnhosphinic chloride (.l). This was confirmed when the acid chloride (l) was reacted with sodium, methoxide to provide the methyl est^r (’ll) with the loss of one halogen atom, and prolonged aqueous alkaline hydrolysis of the .-id chloride (l) afforded the monobasic hydroxy-acid (ill). 6. Ph Ph ! Phpou2 4-' *ph “ 2Wco A 1C] p^pc(C1)P(°)Cl Ph,,C(Cl)P(0)0:' 3 - (X) ’^Gh " (ii) Ph / \ Ou" , ^ (1) Ph? C(0HJP(0)0H 2 (III) ihs Si ructure (l) was confirmed by oreoaring the scid crloride from the hydrolysis product of the Arbusov 40 reaction between dichlorodiohenylmethane and dimethyl phenylohosohonite. Pot.h the expected product <C - chloro-ester (ll) and methylbenzhydrylnhenyl- ~Msrhinate (lu) are r-esur^My formed in Arbusov reaction - .Ph 1 Ph2CC0 + ^h?(C'\e)2 .____ ^ Ph C H P(0)C-,e - (id (XV) ^he reaction mixture could onlv bo successfully separated after acid hvdrolysis which converted (TV) to benzhydrylnhenylohosoMnic acid '"Vi) and hydrolysed both the ou- chloro and methyl qrouns of (n) to give hydroxydinhenylnethylnhenylphosphinic acid (Til). t-'-p-r■: c zo chlorinate (Vt) with M-chlorosuccinimide in the benzylic oc- if ,-n , unsuccessful. 7. Ph Ph I •; t 1 Ph2C(Cl) P(0)0'".e Php C(0H)P(0)0H —ly> •(1) 2 (II) (HI) Ph Ph I 1 Ph.C(H) P(o')C.,'e r~v-> Ph.. C(H)P(0)0H ^ h2° z (iv) (VI) The acid chloride (l) was obtained from the hydroxy-acid (111)(1 mole)