Three component imino-Reformatsky reactions

An enantioselective one-pot, three-component imino-Reformatsky reaction has been reported.20 Combining a benzaldehyde, an aniline, and an alkyl bromoacetate ester, (g) ees of up to 92% have been achieved in the /i-amino ester product, using a recyclable A-methylcphedrinc as auxiliary. A nickel(II) salt and dimethylzinc are employed the latter serves as dehydrating agent, reductant, and coordinating metal. 

The first enantioselective one-pot, three-component imino Reformatsky reactions q have been reviewed 98 (—)-A, A-Dimethylami noisoborneol has been found to be an excellent ligand for the enantioselective addition of Reformatsky reagents to aromatic and aliphatic aldehydes 99 Enantioselectivities up to 93% ee have been obtained with sulfur-containing aldehydes. 

Scheme 4.32 Three-component imino-Reformatsky reaction.

Other types of multicomponent reactions have also been successfully developed, such as the first practical three-component imino-Reformatsky reaction, and a pseudo-three-component reaction between allenes and isocyanates, providing excellent levels of enantioselectivity. Finally, excellent results were described for several novel enantioselective tandem sequences. For example, very high enantioselectivities were reached in tandem Michael/ intramolecular cyclisation sequences, as well as in a remarkable multicat-alytic Michael sequence occurring between enones, alkynes, and DIBAL, which stereoselectively afforded a range of chiral p-alkenyl ketones bearing an all-carbon-substituted quaternary stereogenic centre in excellent enantioselectivities. 

Cozzi, R G., Rivalta, E. (2006). First enantioselective one-pot, three-component imino Reformatsky reaction. Pure and Applied Chemistry, 78, 287-291. 

Scheme 11.5 Imino-Reformatsky type three-component reaction.

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