期刊
JOURNAL OF ORGANIC CHEMISTRY
卷 88, 期 21, 页码 14860-14873出版社
AMER CHEMICAL SOC
DOI: 10.1021/acs.joc.3c00857
关键词
-
In this study, it was discovered that a Pd-catalyzed three-component reaction using 2,5-dihydroxysalicylaldehyde resulted in a mixture of chroman ketal and spiroketal. The selectivity of the reaction was found to be governed by the rate of formation of the o-quinone methide and the isomerization of the initially produced exocyclic enol ether.
Contrary to our previous report in which a Pd-catalyzed three-component reaction of a steroid alkynol, trimethyl orthoformate, and salicylaldehyde exclusively produced chroman ketals, the same reaction employing 2,5-dihydroxysalicylaldehyde led to a mixture of a chroman ketal and a spiroketal. Provided that both courses of the reaction imply a 4 + 2 inverse demand cycloaddition between an o-quinone methide and an enol ether, density functional theory calculations revealed that the chroman ketal/spiroketal selectivity is governed by both, the rate of the formation of the o-quinone methide and the isomerization of the initially produced exocyclic enol ether & horbar;that led to the spiroketal & horbar;to its endocyclic partner that produces the chroman ketal. Remarkably, Lewis catalysis is central to the observed reactivity, and the availability of plausible catalytic species controls the overall chemoselectivity. The methodology herein applied and scrutinized enriches the palette of reactions, leading to increased molecular complexity, as demonstrated in the obtained products, whose antioxidant activity and detailed NMR characterization are presented.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据