Solid-State Photochemistry: Absolute Asymmetric β-Thiolactam Synthesis from Achiral N,N-Dibenzyl-α,β-unsaturated Thioamides

✍ Scribed by Masami Sakamoto; Masaki Takahashi; Wataru Arai; Takashi Mino; Kentaro Yamaguchi; Shoji Watanabe; Tsutomu Fujita

• Book ID: 104202835
• Publisher: Elsevier Science
• Year: 2000
• Tongue: French
• Weight: 213 KB
• Volume: 56
• Category: Article
• ISSN: 0040-4020
• DOI: 10.1016/s0040-4020(00)00501-9

✦ Synopsis

AbstractÐSeveral types of achiral N,N-dibenzyl-a,b-unsaturated thioamides were subjected to X-ray crystallographic analysis, and it was revealed that methylcrotonthioamide and 1-cyclohexenecarbothioamide provided chiral crystals. The absolute con®guration determined by anomalous scattering method corresponded to the cotton effect in the solid-state CD spectra. The solid-state photoreaction gave optically active b-thiolactams. On the other hand, E±Z isomerization takes place in the photoreaction of a tiglylthioamide derivative. Stereochemical assignment before and after the reaction was rationalized by the hydrogen abstraction by alkenyl carbon followed by cyclization via a zwitterionic intermediate.