Norio Miyaura

The Palladium-Catalyzed Cross-Coupling Reaction of Phenylboronic Acid with Haloarenes in the Presence of Bases

Abstract The transition metal-catalyzed reactions of organometallics with organic halides have been extensively studied to prove a new approach to selective formation of carbon-carbon bonds. Recently, such coupling reactions of haloarenes with aryl magnesium1–3 and zinc4 compounds in the presence of palladium or nickel complexes have been reported for the synthesis of biaryls. Davidson and Triggs5 have previously reported that arylboronic acids react with sodium palladate to give the corresponding biaryls in good yields. The synthetic utility of the dimerization reaction is, however, limited because it requires stoichiometric amounts of the palladium compound. On the other hand, we have recently reported that cross-coupling reactions between alkenylboranes and organic halides such as alkenyl,6 alkynyl,6 aryl,7 allyl,8 and benzyl8 halides are effectively catalyzed by a catalytic amount of tetrakis(triphenylphosphine)palladium, Pd(PPh3)4 in the presence of suitable bases as indicated in Scheme 1. Although t...

A new stereospecific cross-coupling by the palladium-catalyzed reaction of 1-alkenylboranes with 1-alkenyl or 1-alkynyl halides

Abstract The representative (E)-1-alkenyldisiamylboranes and (E)-1-alkenyl-1,3,2-benzodioxaboroles readily obtainable via hydroboration of 1-alkynes react with 1-alkenyl halides or 1-alkynyl halides in the presence of a catalytic amount of tetrakis(triphenylphosphine)palladium and base to give corresponding conjugated (E)-dienes or (E)-enynes with high regio- and stereospecificity in good yields, respectively.

SYNTHESIS OF ARYLBORONATES VIA THE PALLADIUM(0)-CATALYZED CROSS-COUPLING REACTION OF TETRA(ALKOXO)DIBORONS WITH ARYL TRIFLATES

Abstract The cross-coupling reaction of (RO)2BB(OR)2 (RO =methoxo and pinacolato) with aryl triflates to give arylboronates was carried out at 80 °C in the presence of PdCl2(dppf) (3 mol%), dppf (3 mol%) and KOAc (3 equivs) in dioxane. The reaction was available with various functional groups such as nitro, cyano, ester, and carbonyl groups.

Chemistry of Group 13 element-transition metal linkage — the platinum- and palladium-catalyzed reactions of (alkoxo)diborons

Abstract The metal-catalyzed borylation of alkenes, alkynes, and organic electrophiles with BB compounds was developed for the synthesis of organoboronic esters from simple organic substrates. The platinum(0)-catalyzed addition of bis(pinacolato)diboron to alkenes and alkynes stereoselectively yielded cis -bis(boryl)alkanes or cis -bis(boryl)alkenes. The addition of diboron to 1,3-dienes with a platinum(0) complex afforded a new access to the cis -1,4-bis(boryl)butene derivatives which are a versatile reagent for diastereoselective allylboration of carbonyl compounds. The cross-coupling reaction of diborons with aryl and vinyl halides or triflates, and allyl chlorides or acetates was found to yield aryl-, vinyl-, and allylboronates in high yields in the presence of a base and a palladium catalyst, which provides the first one-step procedure for the synthesis of organoboronic esters from organic electrophiles. The mechanisms and the synthetic applications of these reactions are discussed.

A borylcopper species generated from bis(pinacolato)diboron and its additions to α,β-unsaturated carbonyl compounds and terminal alkynes

Abstract The addition of bis(pinacolato)diboron [(Me4C2O2)B–B(O2C2Me4)] to α,β-unsaturated carbonyl compounds giving β-boryl carbonyl compounds and the addition to terminal alkynes yielding either 2-boryl-1-alkenes or 1-boryl-1-alkenes were carried out in DMF at room temperature in the presence of CuCl and AcOK. The transmetalation between diboron and [Cu(Cl)OAc]K generating a borylcopper species was proposed as the key step in the reactions because CuOAc similarly mediated both addition reactions to enones and alkynes in the presence of LiCl.

Cross-coupling reaction of organoboron compounds via base-assisted transmetalation to palladium(II) complexes

Abstract Until recently, organoboronic acids have been of limited use in organic synthesis due to their low reactivity for ionic reactions. During the past two decades; however, it has become increasingly clear that they are valuable reagents capable of undergoing many carbon–carbon bond formations in organic syntheses. In 1979, catalytic carbon–carbon bond formation, via transmetalation between organoboron compounds and palladium(II) halides, was found to proceed in the presence of a base.

Iridium-catalyzed C–H coupling reaction of heteroaromatic compounds with bis(pinacolato)diboron: regioselective synthesis of heteroarylboronates

The C–H coupling of aromatic heterocycles with bis(pinacolato)diboron was carried out in octane at 80–100°C in the presence of a 1/2[IrCl(COD)]2-(4,4′-di-tert-butyl-2,2′-bipyridine) catalyst (3 mol%). The reactions of five-membered substrates such as thiophene, furan, pyrrole, and their benzo-fused derivatives exclusively produced 2-borylated products, whereas those of six-membered heterocycles including pyridine and quinoline selectively occurred at the 3-position. Regioselective synthesis of bis(boryl)heteroaromatics was also achieved by using an almost equimolar amount of substrates and the diboron.

Transition metal-catalyzed borylation of alkanes and arenes via CH activation

Abstract Since 1999, direct borylation of hydrocarbons catalyzed by a transition metal complex has been extensively studied by several groups and has become an economical, efficient, elegant, and environmentally benign protocol for the synthesis of a variety of organoboron compounds. Re-, Rh-, Ir- and Pd-catalyzed CH borylation of alkanes, arenes and benzylic positions of alkylarenes by bis(pinacolato)diboron or pinacolborane provide alkyl-, aryl-, heteroaryl- and benzylboron compounds, respectively. In this review, seminal early works and exciting recent developments in the area of direct borylation of hydrocarbons via CH activation are summarized.

Stereoselective synthesis of arylated (E)-alkenes by the reaction of alk-1-enylboranes with aryl halides in the presence of palladium catalyst

The reaction of aryl halides with alk-l-enylboranes, readily obtainable via monohydroboration of acetylenes, provides a conveninet new method for stereoselective synthesis of arylated (E)-alkenes in high yields; these reactions are effectively catalysed by tetrakis(triphenylphosphine)palladium and bases such as sodium ethoxide.

A synthesis of biaryls via nickel(0)-catalyzed cross-coupling reaction of chloroarenes with phenylboronic acids

The cross-coupling reaction of phenylboronic acid with chloroarenes to give biaryls was carried out in high yields at 80 °C in the presence of the nickel(0) catalyst and K3PO4 (3 equivs) in dioxane. The nickel(0) catalyst prepared in situ from NiCl2(dppf) (10 mol%) and four equivalents of BuLi was recognized to be most effective. The reaction can be applicable for a wide range of chloroarenes having an electron-withdrawing or an electron-donating group such as 4-CN-, 4-CHO, 2- or 4-CO2Me, 4-COMe, 4-NHAc, 3- or 4-Me, and 3- or 4-OMe, and 4-NH2.