Applications of vinylogous Mannich reactions. Total syntheses of the ergot alkaloids rugulovasines A and B and setoclavine

…, CL Lynch, AM Fryer, BT Vu, SF Martin

Index: Liras; Lynch; Fryer; Vu; Martin Journal of the American Chemical Society, 2001 , vol. 123, # 25 p. 5918 - 5924

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Citation Number: 79

Abstract

Concise syntheses of the Ergot alkaloids rugulovasine A (3a), rugulovasine B (3b), and setoclavine (2) have been completed by strategies that feature inter-and intramolecular vinylogous Mannich reactions as the key steps. Thus, the first synthesis of 3a, b commenced with the conversion of the known indole 17 into 24 via the addition of the furan 22 to the iminium ion 21, which was generated in situ from the aldehyde 19. Cyclization of 24 by a ...