Copper-catalyzed Enantioselective Conjugate Addition Reactions of Organozinc Reagents

Copper-catalyzed Enantioselective Conjugate Addition Reactions of Organozinc Reagents 

Feringa, Robert Naasz, Rosalinde Imbos, and Leggy A. Arnold 

A number of conjugate additions delivering excellent enantioselectivities through the use of organocuprates in the presence of stoichiometric amounts of chiral (non-transferable) ligands are known today [7-9]. 

A major challenge has been the development of enantioselective 1,4-additions of 

A major problem in the development of catalytic asymmetric 1,4-additions of RLi reagents is the high reactivity usually associated with organolithium species. One solution has been found in the stoichiometric formation of the corresponding chiral cuprates ee s of up to 99% have been reported [20]. An impressive example of the use of a substoichiometric quantity (33 mol%) of chiral ligand is to be found in 

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Feringa, B. L. Naasz, R. Imbos, R. Arnold, L. A. Copper-catalyzed Enantioselective Conjugate Addition Reactions of Organozinc Reagents. In Modem Organocopper Chemistry Krause, N. Ed. Wiley-VCH GmbH Weinheim, 2002 Chapter 7, pp 224—258. 

I 7 Copper-catalyzed Enantioselective Conjugate Addition Reactions of Organozinc Reagents Tab. 7.4. Conjugate additions to 2,5-cyclohexadienone monoacetals and ethers. 

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