Asymmetric cascade annulation based on enantioselective oxa-Diels-Alder cycloaddition of in situ generated isochromenyliums by cooperative binary catalysis of Pd(OAc)2 and (S)-Trip.
Asymmetric cascade annulation based on enantioselective oxa-Diels-Alder cycloaddition of in situ generated isochromenyliums by cooperative binary catalysis of Pd(OAc)2 and (S)-Trip.
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DOI：
10.1021/ja405764p
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发表时间：
2013-07
影响因子：
15
通讯作者：
Shu‐Yan Yu;Hao Zhang;Yang Gao;Lei Mo;Shaozhong Wang;Z. Yao
中科院分区：
文献类型：
--
作者：
Shu‐Yan Yu;Hao Zhang;Yang Gao;Lei Mo;Shaozhong Wang;Z. Yao
基于原位生成的金属异色烯鎓中间体的对映选择性 oxa-Diels-Alder 环加成，通过协同二元催化，在 2-羟基苯乙烯和 2-炔基苯醛或 1-(2-炔基苯基)酮之间建立了不对称级联环化，具有良好至优异的对映选择性（高达 >99.5% ee）。 Pd(OAc)2 和 (S)-Trip。所开发的方法适用于广泛的底物，并且在建立致密的多个手性中心（包括可变桥环系统的季碳）方面表现出极高的效率。机理研究表明(S)-Trip在组装反应物和控制立体选择性方面发挥多种作用。
An asymmetric cascade annulation between 2-hydroxystyrenes and 2-alkynylbenaldehyes or 1-(2-alkynylphenyl)ketones has been established with good to excellent enantioselectivities (up to >99.5% ee), on the basis of an enantioselective oxa-Diels-Alder cycloaddition of in situ generated metallo-isochromenylium intermediates, by cooperative binary catalysis of Pd(OAc)2 and (S)-Trip. The developed methodology is workable for a broad spectrum of substrates and shows great efficiency in establishing dense multiple chiral centers including quaternary carbons of variable bridged ring systems. The mechanism study suggests that (S)-Trip plays multiple roles in assembling the reactants and controlling the stereoselectivity.