Itoh T, Chiba Y, Kawaguchi S, Koitaya Y, Yoneta Y, Yamada K, Abe T. Total synthesis of pyrano[3,2-
e]indole alkaloid fontanesine B by a double cyclization strategy.
RSC Adv 2019;
9:10420-10424. [PMID:
35520921 PMCID:
PMC9062488 DOI:
10.1039/c9ra02321f]
[Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Accepted: 03/27/2019] [Indexed: 12/01/2022] Open
Abstract
The regioselective synthesis of pyrano[3,2-e]indole alkaloid fontanesine B by two different cyclizations is described. The complete regioselectivity is controlled by the C4 Pictet–Spengler cyclization, in which an iminium ion acts as a transient directing (TDG) group. Furthermore, carbolines were constructed by a new Bischler–Napieralski-type cyclization, in which an unprecedented trichloromethyl carbamate serves as a reactive group.
The regioselective synthesis of pyrano[3,2-e]indole alkaloid fontanesine B have been accomplished by C4 Pictet–Spengler cyclization and Bischler–Napieralski-type cyclization of a trichloromethyl carbamate.![]()
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