Transition‐Metal Free Electrophilic Aminations of PolyfunctionalO‐2,4,6‐Trimethylbenzoyl Hydroxylamines with Zinc and Magnesium Organometallics

Abstract

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-AlkylMgCH 2 SiMe 3 .

Preparation of Aromatic and Heterocyclic Amines by the Electrophilic Amination of Functionalized Diorganozincs with Polyfunctional O-2,6-Dichlorobenzoyl Hydroxylamines

“…Although alkyl and highly reactive allylic and benzylic organometallics are mandatory for good amination reactions, 16 an extension to synthetically very important C(sp 2 )-centered organometallics has remained very limited. Herein, we wish to report a solution to this problem and describe a new versatile amination between functionalized di(hetero)arylzincs of type 1 and O-2,6-dichlorobenzoyl hydroxylamines of type 2 leading to a variety of polyfunctional (hetero)arylamines of type 3 using 1,4-dioxane as a key reaction medium and MgCl 2 as an amination promoter (Scheme 1d).…”