Chiral Bronsted Acid Catalyzed Enantioselective Dehydrative Nazarov-Type Electrocyclization of Aryl and 2-Thienyl Vinyl Alcohols
Chiral Bronsted Acid Catalyzed Enantioselective Dehydrative Nazarov-Type Electrocyclization of Aryl and 2-Thienyl Vinyl Alcohols
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DOI：
10.1021/jacs.8b02339
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发表时间：
2018-05-02
影响因子：
15
通讯作者：
Chan, Philip Wai Hong
中科院分区：
文献类型：
--
作者：
Jin, Jianwen;Zhao, Yichao;Chan, Philip Wai Hong
描述了富电子芳基和 2-噻吩基-β-氨基-2-en-1-醇的有效手性布朗斯台德酸催化对映选择性脱水纳扎罗夫型电环化 (DNE)。 4π旋转电环化反应可以得到各种相应的1H-茚和4H-环戊[b]噻吩，产率高达99%，对映体过量（ee）值高达99%。基于所提出的紧密接触离子对物种的实验和计算研究，进一步通过底物阳离子的氨基和手性催化剂阴离子之间的氢键辅助，提供了对观察到的产物对映选择性的深入了解。
An efficient chiral Bronsted acid-catalyzed enantioselective dehydrative Nazarov-type electrocyclization (DNE) of electron-rich aryl- and 2-thienyl-beta-amino-2-en-1-ols is described. The 4 pi conrotatory electrocyclization reaction affords access to a wide variety of the corresponding 1H-indenes and 4H-cyclopenta[b]thiophenes in excellent yields of up to 99% and enantiomeric excess (ee) values of up to 99%. Experimental and computational studies based on a proposed intimate contact ion pair species that is further assisted by hydrogen bonding between the amino group of the substrate cation and chiral catalyst anion provide insight into the observed product enantioselectivities.