Unusual Diastereoselection in the Synthesis of Nine-Membered Ring Lactams and Conformation-Controlled Transannular Reactions to Generate Optically Active Indolizidinones

✍ Scribed by Alexander Sudau; Udo Nubbemeyer

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 131 KB
• Volume: 37
• Category: Article
• ISSN: 0044-8249
• DOI: 10.1002/(sici)1521-3773(19980504)37:8<1140::aid-anie1140>3.0.co;2-w

✦ Synopsis

The aza-Claisen rearrangement of vinylpyrrolidines 1 yielded almost exclusively the trans-3,8-disubstituted nine-membered ring lactams 2 (TBS=tBuMe Si), independent of whether cis or trans isomers were used as starting materials. The conformation (which provided facial chirality) of the medium-sized ring controlled the regio- and diastereoselectivities of the transannular reactions that afforded indolizidinones 3.