Utilization of Industrial Waste Materials, 11. Synthesis of New, Chiral β‐sec‐Amino Alcohols – Diastereodivergent Addition of Grignard Reagents to α‐Amino Aldehydes Based on the (all‐R)‐2‐Azabicyclo[3.3.0]octane System

Abstract

AbstractNew, chiral β‐sec‐amino alcohols (αR,βR)‐11a–13a, (αS,βR)‐11b–17b, (αS,βS)‐11c, 12c, 15c, 17c and (αR,βS)‐11d, 12d, 15d, 17d have been synthesized from the enantiomerically pure amine (all‐R)‐1a via diastereomeric, N‐tert‐butoxycarbonyl‐protected aldehydes 3. Grignard additions proceed in fair yields with a high degree of diastereofacial stereoselection (diastereomeric ratios dr up to ⩾ 95:5) with non‐chelation control, generally in favor of the anti‐(erythro) structures. A mechanistic interpretation of the stereochemical course of this reaction is presented. The stereodifferentiating ability of selected stereoisomeric (erythro)‐ and (threo)‐amino alcohol structures were tested in homogeneous catalysis, e.g. in two model reactions (optical purities up to 95%).