Transition-Metal Free Electrophilic Aminations of Polyfunctional O-2,4,6-Trimethylbenzoyl Hydroxylamines with Zinc and Magnesium Organometallics.

We reported a new electrophilic amination of various primary, secondary and tertiary alkyl, benzylic, allylic zinc and magnesium organometallics with O-2,4,6-trimethylbenzoyl hydroxylamines (O-TBHAs) in 52-99% yield. These O-TBHAs displayed an excellent long-term stability and were readily prepared from various highly functionalized secondary amines via a convenient 3 step procedure. The amination reactions showed remarkable chemoselectivity proceeding without any transition-metal catalyst and were usually complete after 1-3 h reaction time at 25 °C. Furthermore, this electrophilic amination also provided access to enantioenriched tertiary amines (up to 88% ee) by using optically enriched secondary alkylmagnesium reagents of the type s-AlkylMgCH2SiMe3.