Bis-zirconocenes Generated from Weinreb 2-Allylaminoacetamides as Key Intermediates for a Diastereoselective Approach to 2- and 6-Substituted-3-Aminopiperidines

Abstract

The synthesis of 2- and 6-substituted-3-aminopiperidines from Weinreb amides containing an allylamino fragment is reported. Involving the simultaneous hydrozirconation of the C═C and the C═O bonds, the cyclization was promoted by the BF₃-mediated generation of an iminium. Proven to be highly diastereoselective, the sequence can be applied to diversely substituted unsaturated Weinreb amides and valorized through the preparation of bicyclic heterocycles.