Catalytic asymmetric cross-coupling reactions

The literature has been surveyed up to 1988. Some recent reviews relevant to this section are as follows Ni-, Pd-, " and Cu-catalyzed" coupling reactions. Catalytic asymmetric cross-coupling reactions are not treated in this section, since the subject has recently been well reviewed. ... 

Catalytic Asymmetric Cross-Coupling Reactions with Secondary Alkyl Halides... 

A 1,2 or 1,3 unsymmetrically disubstituted arene is prochi-ral and therefore the corresponding chromium tricarbonyl compounds are chiral. (Substituted arene) complexes with amine, carboxyl, and formyl groups at the ortho position are resolved into optically active chromium complexes through corresponding diastereomeric adducts (eq 25). Biocatalysts also perform the kinetic resolution of racemic chromium complexes (eq 26). The optically active chromium complexes can be prepared by di-astereoselective ortho lithiation of the chiral benzaldehyde or acetophenone acetal complexes, and diastereoselective chromium complexation of the chiral ort/io-substituted benzaldehyde am-inals (eq 27). Catalytic asymmetric cross-coupling of meso (1,2-haloarene)chromium complex produces chiral monosubstituted complexes. The chiral (arene)chromium complexes can be used as ligands in asymmetric reactions. ... 

One of the newer and more fmitful developments in this area is asymmetric hydroboration giving chiral organoboranes, which can be transformed into chiral carbon compounds of high optical purity. Other new directions focus on catalytic hydroboration, asymmetric aHylboration, cross-coupling reactions, and appHcations in biomedical research. This article gives an account of the most important aspects of the hydroboration reaction and transformations of its products. For more detail, monographs and reviews are available (1—13). 

The catalytic asymmetric synthesis of allenes was first achieved by Elsevier and co-workers in 1989 [104]. A palladium-catalyzed cross-coupling reaction of an allenyl-metal compound 250 (M = ZnCl, MgCl or Cu) with iodobenzene in the presence of DIOP 251 gave 252 in 25% ee (Scheme 4.65). The synthesis of 252 by the reaction of 250 (M = Br) with phenylzinc chloride in the presence of a chiral palladium catalyst gave a quantitative conversion but very low enantiomeric excesses (3-9% ee). 

Table 8.2 shows the results of the cross-coupling reaction between two differently substituted 2-naphthol derivatives using the CuCl-(5)Phbox catalyst. In conclusion, the first catalytic asymmetric oxidative coupling with a high cross-coupling selectivity was accomplished under mild conditions. 

For recent reviews, see Brase S, de Meijere A (1998) Metal-catalyzed cross coupling reactions. Wiley-VCH, Weinheim Link JT, Overman LE (1998) Metal-catalyzed cross coupling reactions. Wiley-VCH, Weinheim Donde Y, Overman LE (2002) Catalytic asymmetric synthesis, 2nd edn. Wiley-VCH, New York... 

Kantchev EAB, O Brien CJ, Organ MG (2007) Palladium complexes of A-heterocyclic carbenes as catalysts for cross-coupling reactions - a synthetic chemist s perspective. Angew Chem Int Ed 46 2768-2813 Kerr MS, Rovis T (2004) Enantio selective synthesis of quaternary stereocenters via a catalytic asymmetric Stetter reaction. J Am Chem Soc 126 8876-8877 Kerr MS, Read de Alaniz J, Rovis T (2002) A highly enantio selective catalytic intramolecular Stetter reaction. J Am Chem Soc 124 10298-1029 Kerr MS, Read de Alaniz J, Rovis T (2005) An efficient synthesis of achiral and chiral 1,2,4-triazolium salts bench stable precursors for A-heterocyclic carbenes. J Org Chem 70 5725-5728... 

Ravlov, V. A Mechanism of Asymmetric Induction in Catalytic Hydrogenation, Hydrosilylation, and Cross-Coupling Reactions on Metal Complexes, Russ. Chem. Rev. 2002, 71, 39-56. 

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