ChemInform Abstract: Enantioselective Total Syntheses of Ircinal A and Related Manzamine Alkaloids.

✍ Scribed by Stephen F. Martin; John M. Humphrey; Amjad Ali; Michael C. Hillier

• Publisher: John Wiley and Sons
• Year: 2010
• Weight: 36 KB
• Volume: 30
• Category: Article
• ISSN: 0931-7597
• DOI: 10.1002/chin.199925195

✦ Synopsis

Enantioselective Total Syntheses of Ircinal A and Related Manzamine Alkaloids.

-The enantioselective total synthesis of ircinal A (VIII) is presented involving a novel tandem Stille coupling-[4 + 2] cycloaddition reaction and two ring-closing metathesis reactions as the key steps. Thus, Stille coupling of bromovinylcarboxylate (I) with vinylstannane (II) affords a 1,3-diene intermediate which subsequently undergoes Diels-Alder reaction with the pyrroline double bond to furnish pyrrolo-fused isoquinoline (III) in good yield. In this tandem reaction, the single stereocenter at the pyrroline ring defines the relative and absolute stereochemistry in the tricyclic ABC subunit of the ircinal skeleton. Two ring-closing metathesis reactions in the presence of Grubbs catalyst Ph-CH=RuCl 2 (PCy 3 ) 2 provide access to the thirteen-and eight-membered D-and E-rings, respectively. -(MARTIN, STEPHEN F.;