Rodríguez-Caro JF, Afonso MM, Palenzuela JA. A Simple Entry to the 5,8-Disubstituted Indolizidine Skeleton via Hetero Diels-Alder Reaction.
Molecules 2023;
28:7316. [PMID:
37959735 PMCID:
PMC10647431 DOI:
10.3390/molecules28217316]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Revised: 10/25/2023] [Accepted: 10/26/2023] [Indexed: 11/15/2023] Open
Abstract
The 5,8-disubstituted indolizidines are the largest family of indolizidines isolated from the skin of amphibians. These compounds exhibit interesting biological activities such as noncompetitive blockers of nicotinic receptors. In this paper, we present a short, simple, and general synthesis of these alkaloids based on the hetero Diels-Alder reaction between suitable monoactivated dienes and Δ1-pyrroline as the dienophile. The selectivity of the process is explained based on computational studies. Concise synthesis of the indolizidine alkaloid 181B from a hetero Diels-Alder reaction was accomplished in four steps.
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