カスケード型ラジカル環化反応の立体制御研究

抄録

Our laboratory is interested in developing the effective cascade reactions based on radical chemistry. Recently, we have reported the stereocontrol strategy that takes advantage of the hydroxamates. The control of the rotamer population would be crucial for achieving high enantioselectivity in radical cyclization. In cascade radical cyclization, hydroxamate acted as a coordination site with Lewis acid, and a high degree of stereocontrol was achieved probably due to the predominant formation of single reactive rotamer. In the case of substrate having acrylate moiety, the reaction with an isopropyl radical proceeded smoothly in the presence of box ligand and zinc Lewis acid to give the cyclic product with 92% ee. Excellent enantioselectivities were also observed in the reaction of other substrates.

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