Formal [5+1] annulation reactions of dielectrophilic peroxides: facile access to functionalized dihydropyrans
Chen Zhong1, Qi Yin, Yukun Zhao
1Chongqing Key Laboratory of Natural Product Synthesis and Drug Research, School of Pharmaceutical Sciences, Chongqing University, Chongqing 401331, China. lhu@cqu.edu.cn.
Abstract:
A general [5+1] annulation reaction, which utilized 4-bromo- or 4-mesyloxy-but-2-enyl peroxides as unique five-atom bielectrophilic synthons to participate in the C-C and the subsequent umpolung C-O bond-forming reactions with C1 nucleophiles, has been developed for the facile synthesis of 2,2-disubstituted dihydropyrans in high yields under mild basic conditions. The dihydropyrans, which are readily prepared on a gram scale by this new method, can be flexibly transformed into the biologically important tetrahydropyrans and pyranones in 1-2 steps.
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