Conjugate Addition Reactions of α-Aminoalkylcuprates with α,β-Enones and Enals

✍ Scribed by R. Karl Dieter; Christopher W. Alexander; Lois E. Nice

• Publisher: Elsevier Science
• Year: 2000
• Tongue: French
• Weight: 218 KB
• Volume: 56
• Category: Article
• ISSN: 0040-4020
• DOI: 10.1016/s0040-4020(00)00130-7

✦ Synopsis

AbstractÐDeprotonation of Boc-protected amines with sec-BuLi or transmetallation of a-aminostannanes with n-BuLi affords a-aminoalkyllithium reagents which can be converted into a-aminoalkylcuprate reagents with CuCN or THF soluble CuCN´2LiCl. These reagents undergo conjugate addition reactions with a,b-enones and enals. Reagents prepared from 2 equiv. of the a-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 a-aminoalkyl ligand, is preferred. The Boc protecting group can be removed with PhOH/TMSCl and the amino ketone isolated as the hydrochloride salt.