Novel generation of azomethine imines from α-silylnitrosamines by 1, 4-silatropic shift and their cycloaddition

KI Washizuka, K Nagai, S Minakata, I Ryu, M Komatsu

Index: Washizuka, Ken-Ichi; Nagai, Keiko; Minakata, Satoshi; Ryu, Ilhyong; Komatsu, Mitsuo Tetrahedron Letters, 1999 , vol. 40, # 50 p. 8849 - 8853

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Citation Number: 34

Abstract

Novel and facile generation of azomethine imines from α-silylnitrosamines and subsequent cycloaddition with dipolarophiles leading to a variety of pyrazole derivatives have been developed. The key to the reaction is a 1, 4-silatropic shift caused by strong affinity of the nitroso oxygen atom toward the silicon atom. Thus, α-silylnitrosamines are treated with 1 equiv. of dipolarophiles in refluxing toluene for 1 h to give pyrazole derivatives in good to ...