Synthesis of functionalized cyclic enamines from lithium alkylphenyl sulfones and N-carbo-tert-butoxy lactams

✍ Scribed by Luis A. Arias; David Arbelo; Arnaldo Alzérreca; José A. Prieto

• Publisher: Journal of Heterocyclic Chemistry
• Year: 2001
• Tongue: English
• Weight: 68 KB
• Volume: 38
• Category: Article
• ISSN: 0022-152X
• DOI: 10.1002/jhet.5570380104

✦ Synopsis

Abstract

Alkylphenyl sulfones 3 are appropriate synthons for the synthesis of 2‐phenylsulfonyl alkylidene pyrro‐lidine or piperidine derivatives 1 in good to moderate yields. The lithium alkyl sulfones 4 are first reacted with the desired protected lactams and then subjected to acidic methanolysis to afford the unusual enam‐ines 1a‐e. NMR studies (COSY ^1^H‐^1^H, COSY ^1^H‐^13^C, NOE) showed the Z enamines to exist in a dynamic equilibrium with the corresponding imines 2. The stereochemistry of the described compounds was confirmed by molecular calculations.