Vinylogous Mannich reactions. Stereoselective formal synthesis of pumiliotoxin 251D

✍ Scribed by Stephen F. Martin; Scott K. Bur

• Book ID: 104209487
• Publisher: Elsevier Science
• Year: 1999
• Tongue: French
• Weight: 669 KB
• Volume: 55
• Category: Article
• ISSN: 0040-4020
• DOI: 10.1016/s0040-4020(99)00452-4

✦ Synopsis

A concise synthesis of (-)-3, a known precursor of pumiliotoxin 251D, has been completed using a vinylogous Mannich reaction as a key construction. Silyloxyfuran 10 added to methoxypyrrolidine 20 in the presence of TMS-OTf to give a mixture (4.8:1) of 21 and 22 in 57% yield. Reduction and global deprotection of 21 afforded the bicyclic lactam 23. Raney Nickel mediated extrusion of the hydroxymethyl group from 23 gave (-)-3.