Titanium(IV)-Catalyzed Stereoselective Synthesis of Spirooxindole-1-pyrrolines

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• 作者：Joseph J. Badillo ; Carlos J. A. Ribeiro ; Marilyn M. Olmstead ; Annaliese K. Franz
• 刊名：Organic Letters
• 出版年：2014
• 出版时间：December 19, 2014
• 年：2014
• 卷：16
• 期：24
• 页码：6270-6273
• 全文大小：400K
• ISSN：1523-7052

文摘

A stereoselective cyclization between alkylidene oxindoles and 5-methoxyoxazoles has been developed using catalytic titanium(IV) chloride (as low as 5 mol %) to afford spiro[3,3鈥?oxindole-1-pyrrolines] in excellent yield (up to 99%) and diastereoselectivity (up to 99:1). Using a chiral scandium(III)鈥搃ndapybox/BArF complex affords enantioenriched spirooxindole-1-pyrrolines where a ligand-induced reversal of diastereoselectivity is observed. This methodology is further demonstrated for the synthesis of pyrrolines from malonate alkylidene and coumarin derivatives.