Imines, reaction with organozinc reagents

Reactions of Organozinc Reagents with Imines and Other C=N... 

Quite recently, there has been significant expansion and development in the alkylation of imines with organozinc reagents using chiral Lewis acid catalysts. In 2000, Tomioka and co-workers reported a copper(II)-chiral amidophos-phine 4-catalyzed asymmetric process for the addition of diethylzinc to N-sul-fonylimines (Scheme 2) [8]. Excellent enantioselectivities (90-94%) and yields (83-99%) were obtained in reactions of N-sulfonylimines derived from arylal-dehydes. 

Enantiomerically enriched or pure benzaldehydeimine complexes react with nucleophiles such as Grignard see Grignard Reagents) and organozinc reagents, and they participate in a number of cycloaddition reactions. Enantiopure tricyclic /3-lactams can be obtained from stereoselective [2 - - 2]cycloaddition between a complexed chiral benzaldehyde imine and a ketene (Scheme 85). For example, reaction of (44) with acetoxyketene gives (45). 

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