Lewis Acid Assisted Vinylogous Mannich and Mukaiyama Aldol Reactions: A Route to Densely Hydroxylated Indolizidine Alkaloid Analogues

✍ Scribed by Gloria Rassu; Paola Carta; Luigi Pinna; Lucia Battistini; Franca Zanardi; Domenico Acquotti; Giovanni Casiraghi

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 276 KB
• Volume: 1999
• Category: Article
• ISSN: 1434-193X
• DOI: 10.1002/(sici)1099-0690(199906)1999:6<1395::aid-ejoc1395>3.0.co;2-t

✦ Synopsis

The hydroxymethyl-substituted indolizidines 6 and 7, scantily exploited vinylogous version of the Mannich reaction. The key iminium electrophilic acceptor 11 is, in representative members of a ring-B-expanded alexineaustraline subclass, are readily accessible by starting with turn, available through a vinylogous intermolecular Mukaiyama aldolization process between pyrrole-based furan-based silyloxydiene 12 and hydroxymethyl hemiaminal 11, through a synthesis sequence involving a silyloxydiene 8 and (S)-glyceraldehyde 9.