Organocatalytic enantioselective construction of multi-functionalized spiro oxindole dienes
作者:Xiao-Fei Huang、Ya-Fei Zhang、Zheng-Hang Qi、Nai-Kai Li、Zhi-Cong Geng、Kun Li、Xing-Wang Wang
DOI:10.1039/c4ob00545g
日期:——
A diastereo- and enantio-selective domino Michael-cyclization–tautomerization reaction of isatylidene malononitriles with α,α-dicyanoalkenes catalyzed by a cinchona alkaloid-derived bifunctional thiourea catalyst has been developed. A series of multi-functionalized spiro oxindole diene derivatives have been obtained in good to excellent yields (up to 97%) with good to excellent enantioselectivities (up to 96%) as well as good diastereoselectivities (up to 7.9 : 1). In addition, an anomalous temperature effect on the enantioselectivity has also been studied for this transformation.
Enantioselective sequential vinylogous Michael addition–cyclization reactions of vinyl malononitriles with isatylidene malononitrile were accomplished usingl-proline derived bifunctional thiourea.