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Palladium-Catalyzed Cross-Coupling Reactions of Organoboron Compounds

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Palladium-Catalyzed Cross-Coupling Reactions of Organoboron Compounds Chem. Rev. 1995, 95,2457-2483 2451 Palladium-Catalyzed Cross-Coupling Reactions of Organoboron Compounds Norio Miyaura' and Akira Suzuki'nt DivisMn of Molecukr Chemistry, FacuKy of Engfm~ing,Hokkaa Univemw, Sappew NO, Japan RWJanuary 31, 1995 (Revised Manmpt Received August 17, lN5) Contents I. lntmduction 2457 II. Svnthesis of Omanoboron Reaoents 2458 A Synthesis frk Organoliihiim or Magnesium 2458 Reagents '1 B. Hydroboration of Alkenes and Alkynes 2458 C. Haioboration of Teninal Alkynes 2459 D. Miscellaneous Methods 2459 111. Palladium-Catalyzed Reactions of Organoboron 2460 Compounds and Their Mechanism A. Cross-Cowlino Reaction 2460 B. Other Catalyti; Process by Transition-Metal 2464 Complexes IV. Cross-Coupling Reaction 2465 Norio Myaura was bom in Hokkaido. Japan in 1946. He received his A. Coupling of 1-Alkenylboron Derivatives: 2465 BSc. and his Dr. from Hokkaido University. He became a research Synthesis of Conjugated Dienes assffiiate and an asscciate professor of A. Suzuki's research group and 6. Coupling of Arylboron Derivatives: Synthesis 2469 was promoted to the professor of the same group in 1994. In 1981, he of Biaryls joined J. K. Kochi research group at Indiana Universily and studied the C. Coupling of Alkylboron Derivatives 2471 catalylic and noncatalytic epoxidation of alkenes wth oxwmetal reagents. His current interests are mainly in the field of transition-metalcatalyzed Coupling with Triflates D. 2473 reaclions of organoboron compounds, with emphasis on applications to E. Synthesis of Vinylic Sulfides 2473 organic synthesis. For examples, crosscoupling reaction, catalytic F. Coupling with lodoalkanes: Alkyl-Alkyl 2475 hydroboration, catalytic thioboration, and catalytic diboration of alkenes CouDlino and alkynes. G. Coupling with Other Organic Halides and 2475 Boron Reagents V. Head-to-Tail Coupling 2476 VI. Carbonylative Coupling 2476 VII. Alkoxycarbonylation and Dimerization 2478 VIII. Conclusion 2478 1. Introduction The cross-coupling reaction now accessible via a variety of organometallic reagents may provide a fundamentally common synthetic methodology (eq 1). Pdcataiyal R-M + R'-X 111 Ra' Akira Suzuki was born n Ho%kaoo.Japan In 1930 He received his undergraduate ana graoLate Iran ng at ho66aido Jniversily and joined In 1972, Kumada and Tamao' and Corriu2 reported the lacully in 1961 as an assistant professor. he spent two years as a independently that the reaction of organomagnesium postdoctoral associate w In Professor herben C. Brown a1 PurdJe reagents with alkenyl or aryl halides could be mark- Universty ana was promoled 10 Ine rank 01 professor in 1971. Alter edly catalyzed by Ni(I1) complex. Kochi3 found the reirement from Hokkaido Ln'versry. Akira SJZLki moved to Okayama Univers of Sc ence as a cnemtstry professor in 1994. current efficiency ofFe(II1) catalyst the cross-coupling of ty His for inleresis are ma nly n lne hela of organoboron cnemisly. with empnasis Grignard reagents with 1-halo-1-alkenes and Liz- on app catlons to organ c syntnes s. organometal IC chemistry, an0 tne CuClr catalyst for haloalkanes. The palladium- study 01 reactive interned ales catalyzed reaction of Grignard reagents was first reported by Murahashi? the synthetic utility ofwhich reagents. After those discoveries, many other orga- was then amply demonstrated by Negishi5 on the nometallic reagents have proven to be highly useful reactions of organoaluminum, zinc, and zirconium as nucleophiles for the cross-coupling reaction, e.g., organolithiums by Murahashi: organostannans by 'Resent address: Kurashiki University of Seience and the Arts, Migita' and Stille? 1-alkenylcopper(1) by Normant? Kurashiki 712, Japan. organosilicon compounds by Hiyama.'O These reac- 0009-2665/95/0795-2457$15.5010 0 1995 American Chemical Society 2458 Chemical Reviews, 1995, Vol. 95, No. 7 Miyaura and Suzuki tions are mechanically and synthetically closely H30+ related to the present article; however, the reactions, ArMgX + B(OMe), -- ArB(OH)2 (2) mechanism, and their synthetic utility have been extensively reviewed elsewhere.'l CH,=CHMgBr + B(OMe), -2- CH2=CHB(OR)2 (3) Organoboron compounds are highly electrophilic, but the organic groups on boron are weakly nucleo- philic, thus limiting the use of organoboron reagents for the ionic reactions. The coordination of a nega- tively charged base to the boron atom has been recognized to be an efficient method of increasing its aryl-, 1-alkynyl-, and 1-alkenylboronic esters in high nucleophilicity to transfer the organic group on boron yields, often over 90% (eq 5).23Triisopropyl borate to the adjacent positive center (1,2-migration reac- is shown to be the best of available alkyl borates to tion).12 However, intermolecular transfer reaction avoid such multiple alkylation of the borates. such as the Grignard-like reaction are relatively rare. HCI Fortunately, organoboron compounds, even orga- RLi + B(OPrj3 -R-B(OPi3 - R-B(OP& (5) noboronic acids and esters, have sufficiently enough R = alkyl, aryl, 1-alkenyl, and 1-alkynyl reactivity for the transmetalation to other metals. Transmetalations to silver(I),13magne~ium(II),'~ zinc- Very recently, arylboronic esters have been directly (11),15aluminum(II),lG tin(IV),17 copper(I),ls and mer- obtained from aryl halides via the cross-coupling cury(II)lghalides have been extensively studied. In reaction of (a1koxy)diboron (eq 6).24 The reaction 1978, Negishi reported that iodobenzene selectively tolerates various functional groups such as ester, couples with the 1-alkynyl group on lithium l-hex- nitrile, nitro, and acyl groups. ynyl(tributy1)borate through a palladium-catalyzed addition-elimination sequence (Heck-type pro~ess);~' however, the cross-coupling reaction of organoboron compounds, which involves the transmetalation to palladium(I1) halides as a key step, was found to proceed smoothly .when these were activated with suitable bases and have proven to be a quite general B. Hydroboration of Alkenes and Alkynes technique for a wide range of selective carbon-carbon The addition of dialkylboranes such as 9-borabicyclo- bond formation.20 Many organometallic reagents [ 3.3. llnonane (9-BBN), disiamylborane, or dicyclo- undergo similar cross-coupling reactions, but much hexylborane to 1-alkenes gives mixed alkylboron attention has recently been focused on the use of compounds.25 The reaction is essentially quantita- organoboronic acids in laboratories and industries tive, proceeds through cis anti-Markovnikov addition since they are convenient reagents, which are gener- from the less hindered side of double bond, and can ally thermally stable and inert to water and oxygen, tolerate various functional groups. The 9-alkyl-9- thus allow their handling without special precau- BBN derivatives thus obtained are particularly use- tions. This review summarizes the palladium- ful for the transfer of primary alkyl groups by the catalyzed cross-coupling reaction of organoboron palladium-catalyzed cross-coupling reaction since the compounds with organic halides or triflates, the 9-alkyl group exclusively participates in a catalytic reaction mechanism, the scope of synthetic applica- reaction cycle (eq 7). tions, and other related catalytic processes with transition-metal complexes are discussed.20 11. Synthesis of Organoboron Reagents 1 : 9-R-9-BBN A. Synthesis from Organolithium or Magnesium The use of the hydroboration reaction is especially Reagents valuable for the synthesis of stereodefined or func- The classical synthesis of aryl- and l-alkenylbo- tionalized alkenylboronic acids and their esters. The ronic acids or their esters from Grignard reagents or general and most convenient method is the hydrobo- lithium reagents and trialkyl borates is an efficient ration of a terminal alkyne with catecholborane (2a) method for making relatively simple boron com- to produce 1-alkenylboronic ester (eq 8).25,26The pounds in large quantities (eqs 2 and 3121 The first hydroboration with 2a can also be carried out under stereocontrolled synthesis of alkenylboronic acids and milder conditions by using palladium, rhodium, or esters involves the reaction of a (2)-or (E1-2-buten- nickel ~atalysts.~~The hydroboration of alkynes with 2-ylmagnesium bromide with trimethyl borate (eq dihaloboranes (HBClySMe2 or HBBr2mSMe2), fol- 41.22 lowed by hydrolysis to vinylboronic acids or alcoholy- However, the application of these classical proce- sis to boronic esters (3b)have been used for the same dures for organoboronic acid or ester synthesis may p~rpose.~~,~~However, a recent and more convenient suffer from the contamination of small mount of the variant is the in situ preparation of HBClz in a opposite stereoisomers, or bis-alkylation leading to hydrocarbon solvent from BC13 and HSiEt3.29 The the borinic acid derivatives and the formation of reagent exhibits extremely high reactivity to alkenes trialkylboranes. A recent useful variant utilizes and alkynes allowing the hydroboration to proceed organolithium reagents and triisopropyl borate, fol- at -78 "C. Disiamylborane (2c) is also one of the lowed by acidification with HC1 to give directly alkyl-, mildest and selective hydroboration reagents for Reactions of Organoboron Compounds Chemical Reviews, 1995, Vol. 95, functionalized alkynes, but their use for the cross- X R' CrC -X 1.HBBrpSMez coupling can be more difficult than that of boronic - R1+O(Oprj, acids or their esters. Hydroboration of terminal 2. iPrOH 4a:~=~r alkynes with 9-BBN leads to the formation of sig- 4b: X= I nificant quantities of dihydroboration products.
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