Conjugate addition reactions of alpha-aminoalkylcuprates with alpha,beta-enones and enals

Deprotonation of Boc-protected amines with sec-BuLi or transmetalation of a lpha-aminostannanes with n-BuLi affords alpha-aminoalkyllithium reagents wh ich can be converted into alpha-aminoalkylcuprate reagents with CuCN or THF soluble CuCN . 2LiCl. These reagents undergo conjugate addition reactions with alpha,beta-enones and enals. Reagents prepared from 2 equiv. of the al pha-aminoalkyllithium reagent give higher yields of conjugate adducts than those prepared from RCuCNLi, particularly when insoluble CuCN is employed. When CuCN . 2LiCl is used, the two cuprate reagents give comparable yields of 1,4-adducts and the RCuCNLi reagent, economical in alpha-aminoalkyl liga nd, is preferred. The Boc protecting group can be removed with PhOH/TMSCl a nd the amino ketone isolated as the hydrochloride salt. (C) 2000 Elsevier S cience Ltd. All rights reserved.