Synthesis 2022; 54(06): 1577-1586
DOI: 10.1055/a-1681-4067
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A Flexible Approach to the Synthesis of Type II and III Lepadin Alkaloids

Yue Hu
,
He Gu
,
Yuanliang Jia
,
Guiyin Luo
,
Xiaochuan Chen
This work was supported by grants from the National Natural Science Foundation of China (21172153, 22171190), the Sichuan Science and Technology Program (2019YJ0032) and the Fundamental Research Funds for the Central Universities.


Abstract

A flexible approach to both type II and III lepadin alkaloids is developed for the first time. A key Diels–Alder reaction based on a novel chiral ketolactone dienophile is employed to obtain the desirable all-cis-trisubstituted cyclohexene with excellent regio- and stereoselectivity. As the subsequent closure of the piperidine ring is devised at the N1 and C2 position via an intramolecular nucleophilic amination, the two stereochemical types of lepadin frameworks with the opposite configuration at C2 can be conveniently accessible from a common intermediate. By the approach, lepadins D, E (type II) and F (type III) are stereo­selectively synthesized from ethyl l-lactate.

Supporting Information



Publication History

Received: 24 September 2021

Accepted after revision: 28 October 2021

Accepted Manuscript online:
28 October 2021

Article published online:
16 December 2021

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