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Published on: May 26, 2019
Organocatalytic conjugate addition of malononitrile to conformationally restricted dienones
Zhi-Peng Hu1, Chun-Liang Lou, Jin-Jia Wang
1Institute of Drug Synthesis and Pharmaceutical Process, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou 510006, China.
Abstract:
Organocatalytic conjugate addition of malononitrile to conformationally restricted dienones has been studied. A series of chiral primary and tertiary amine catalysts were screened. A piperidine-based thiourea-tertiary amine was found to be the efficient catalyst. Chiral pyran derivatives were obtained in excellent yields and enantioselectivities via a cascade conjugate addition-intramolecular cyclization pathway. The reaction is remarkably different for the corresponding reaction of conformationally flexible dienones.
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