期刊
JOURNAL OF ORGANIC CHEMISTRY
卷 77, 期 6, 页码 2588-2607出版社
AMER CHEMICAL SOC
DOI: 10.1021/jo202179s
关键词
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资金
- Japan Society for the Promotion of Science (JSPS)
- Grants-in-Aid for Scientific Research [23681045, 21241050, 23102016] Funding Source: KAKEN
Intramolecular oxa-conjugate cyclization (IOCC) of alpha,beta-unsaturated carbonyl compounds, triggered by deprotonation with a base, represents a straightforward method for the synthesis of tetrahydropyrans. However, it has been known that stereochemical outcome of IOCC depends on the local structure substrates and sometimes requires harsh reaction conditions and/or prolonged reaction times for selective formation of 2,6-cis-substituted tetrahydropyrans. These shortcomings limit the feasibility of IOCC in the context of complex natural product synthesis. In this paper, we describe Bronsted acid-catalyzed IOCC of alpha,beta-unsaturated ester surrogates (e.g., alpha,beta-unsaturated thioesters, oxazolidinone imides, and pyrrole amides) under mild reaction conditions, which affords a series of synthetically versatile 2,6-cis-substituted tetrahydropyran derivatives with good to excellent stereoselectivity (dr from 7:1 to >20:1). These alpha,beta-unsaturated carbonyl compounds were found to be more reactive than the corresponding oxoesters that are generally unreactive toward Bronsted acid-catalyzed intramolecular oxa-conjugate additions. The product tetrahydropyrans could be transformed into various derivatives in an efficient manner, highlighting the usefulness of our methodology.
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