Organocatalytic Domino Oxa-Michael/1,6-Addition Reactions: Asymmetric Synthesis of Chromans Bearing Oxindole Scaffolds
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- 作者：Kun Zhao ; Dr. Ying Zhi ; Tao Shu ; Dr. Arto Valkonen ; Prof. Dr. Kari Rissanen and Prof. Dr. Dieter Enders
- 刊名：Angewandte Chemie
- 出版年：2016
- 出版时间：September 19, 2016
- 年：2016
- 卷：128
- 期：39
- 页码：12283-12287
- 全文大小：1157K
- ISSN：1521-3757
文摘
An asymmetric organocatalytic domino oxa-Michael/1,6-addition reaction of ortho-hydroxyphenyl-substituted para-quinone methides and isatin-derived enoates has been developed. In the presence of 5 mol % of a bifunctional thiourea organocatalyst, this scalable domino reaction affords 4-phenyl-substituted chromans bearing spiro-connected oxindole scaffolds and three adjacent stereogenic centers in good to excellent yields (up to 98 %) and with very high stereoselectivities (up to >20:1 d.r., >99 % ee).