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A Simple Procedure for the Synthesis of β-Hydroxyallenamides via Homoallenylation of Aldehydes

Research paper by Byeong‐Seon Kim, Osvaldo Gutierrez, Marisa C. Kozlowski, Patrick J. Walsh

Indexed on: 28 Feb '18Published on: 20 Feb '18Published in: Advanced Synthesis & Catalysis



Abstract

A simple one-pot synthesis of β-hydroxyallenamides is reported. This procedure entails chemo- and regioselective hydroboration of 3-en-1-ynyl-sulfonylamides with Cy2BH followed by homoallenylation of aldehydes to yield β-hydroxyallenamides (up to 94% yield and >20:1 dr). Controlled synthesis of up to three continuous stereochemical elements was realized. Density functional theory (DFT) calculations suggest a concerted Zimmerman-Traxler chair-like transition state. Initial results suggest that enantio- and diastereoselective synthesis of β-hydroxyallenamides with optically active hydroboration reagents is viable.