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.
General approach to a spiro indole-3,1′-naphthalene tetracyclic system: stereoselective pseudo four-component reaction of isatins and cyclic ketones with two molecules of malononitrile
作者:M. N. Elinson、A. N. Vereshchagin、R. F. Nasybullin、S. I. Bobrovsky、A. I. Ilovaisky、V. M. Merkulova、I. S. Bushmarinov、M. P. Egorov
DOI:10.1039/c5ra03452c
日期:——
with two molecules of malononitrile catalyzed by triethylamine at ambient temperature stereoselectively results in the formation of tetracyclicspirooxindoles in 60–90% yields. Thus, a new simple and efficient ‘one-pot’ method to synthesize substituted spirooxindoles was found directly from reasonable starting compounds. Unique stereoselectivety was achieved on two or three centers in this pseudo four-component