Synthesis of 4‐Substituted Piperidines via a Mild and Scalable Two‐Step Cu2O‐Mediated Decarboxylation of Cyanoesters

Abstract A four‐step, high‐yielding, kilogram‐scale protocol to prepare aldehyde 5 is reported. The key reaction is a mild, two‐step Cu2O‐mediated decarboxylation of cyanoester 3 that proceeds in excellent yield. The general applicability of this methodology has also been explored.