First Synthesis of Medium-Sized Ring Allenyl Lactams

✍ Scribed by Moritz Perscheid; Dieter Schollmeyer; Udo Nubbemeyer

• Publisher: John Wiley and Sons
• Year: 2011
• Tongue: English
• Weight: 129 KB
• Volume: 2011
• Category: Article
• ISSN: 1434-193X
• DOI: 10.1002/ejoc.201100830

✦ Synopsis

Abstract

Medium‐sized lactams bearing an axially chiral allene unit have been synthesized by using an aza‐ketene Claisen rearrangement. Starting from 2‐alkynylpiperidines or 2‐alkynylazepines, ring enlargement enabled the highly diastereoselective formation of 10‐ or 11‐membered lactams with a 4,5‐allene subunit. X‐ray analysis of the allenylacezinone showed the presence of a strained cumulated olefin system with a defined arrangement of the functional groups. The cyclic allenes were found to be stable upon heating up to 50 °C.