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Retropinacol/Cross-pinacol Coupling Reactions - A Catalytic Access to 1,2-Unsymmetrical Diols
Published on: April 4, 2014
Titanocene(III)-Catalyzed Three-Component Reaction of Secondary Amides, Aldehydes, and Electrophilic Alkenes
Xiao Zheng1,2, Jiang He3, Heng-Hui Li3
1Department of Chemistry and The Key Laboratory for Chemical Biology of Fujian Province, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, Fujian 361005 (P.R. China). zxiao@xmu.edu.cn.
Abstract:
An umpolung Mannich-type reaction of secondary amides, aliphatic aldehydes, and electrophilic alkenes has been disclosed. This reaction features the one-pot formation of C-N and C-C bonds by a titanocene-catalyzed radical coupling of the condensation products, from secondary amides and aldehydes, with electrophilic alkenes. N-substituted γ-amido-acid derivatives and γ-amido ketones can be efficiently prepared by the current method. Extension to the reaction between ketoamides and electrophilic alkenes allows rapid assembly of piperidine skeletons with α-amino quaternary carbon centers. Its synthetic utility has been demonstrated by a facile construction of the tricyclic core of marine alkaloids such as cylindricine C and polycitorol A.
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