Uncatalyzed cationic olefin cyclizations of N-vinylic α-chloro-α-thioacetamides. Formation of β-and γ-lactams

…, T Nakaharu, M Nishimura, A Nishikawa, C Kameoka…

Index: Ishibashi, Hiroyuki; Nakaharu, Tohru; Nishimura, Masako; Nishikawa, Atsuko; Kameoka, Chisato; Ikeda, Masazumi Tetrahedron, 1995 , vol. 51, # 10 p. 2929 - 2938

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Citation Number: 12

Abstract

N-Vinylic α-chloro-α-thioacetamides were found to cyclize without a catalyst in two different manners depending upon the nature of the substituents at the terminus of the N-vinylic bond. Thus, bis (phenylthio)-substituted enamides 8a-c cyclized in a 4-exo-trig manner to give 4- methylene-β-lactams 10a-c, whereas mono (phenylthio)-, monophenyl-, diphenyl-, and dialkyl-substituted congeners 23a, b, 28, and 38 cyclized in a 5-endo-trig manner to give γ ...