Coupling reactions of organometallic

A general catalytic cycle for the cross-coupling reaction of organometallics involves an oxidative addition-transmetallation-reductive elimination sequence, as depicted in Scheme... 

This protocol and the Pd-Cu-catalyzed direct cross-coupling with terminal acetylenes (Section 5.3.5) directly complement each other. The following examples, which cannot be applied to the latter, give normal coupling products only by Stille method [Eqs. 17-20] [28-31]. This method is especially useful for the cross-coupling reactions of organometallic complexes with cyclopentadienyl ligand that are sensitive to amines [Eq. 19] [30]. 

Nickel and Palladium Complex Catalyzed Cross-Coupling Reactions of Organometallic Reagents with Organic Halides. 

Chemey AH, Kadunce NT, Reisman SE (2015) Enantioselective and enantiospecific transition-metal-catalyzed cross-coupling reactions of organometallic reagents to construct C-C bonds. ChemRev 115 9587-9652... 

M. Kumada, Nickel and Palladium Cross-Coupling Reactions of Organometallic Reagents with Organic Halides , Pure Appl. Chem., 1980, 52, 669. 

D) Palladium catalyzed cross-coupling reactions of organometallics [26] have been developed to a very valuable S30ithetic tool and have received applications in natural product chemistry the vinylalane case being a particular but useful one as such alanes are readily available by zirconium catalyzed carboalumination of acetylenes. More classical organometallics have also been successfully used for such coupling reactions. 

Carbonylative cross-coupling reactions of organometallic compounds with organic halides have been extensively studied and reported to provide excellent methods for the synthesis of unsymmetrical ketones [86]. The general catalytic cycle for this carbonylative coupling reaction is analogous to that of nucleophile except for the transmetalation step (Scheme 9.21). 

The cross-coupling reactions of organometallic reagents with organic electrophiles in the presence of transition state metal catalysts, based mostly on nickel or palladium metal, has emerged as a powerful tool for the synthesis of both natural and unnatural compounds. Great advances in the field have included the development of new metal complexes for asymmetric catalytic reactions that can be carried out under mild conditions even with deactivated or steri-cally hindered substrates. 

---