Thermal or Lewis acid-promoted electrocyclisation and hetero Diels–Alder cycloaddition of α, β-unsaturated (conjugated) carbodiimides: a facile synthesis of nitrogen- …

…, K Tsuda, T Karakasa, S Satsumabayashi

Index: Saito, Takao; Ohkubo, Takahiro; Kuboki, Hideki; Maeda, Masayuki; Tsuda, Kensaku; Karakasa, Takayuki; Satsumabayashi, Sadayoshi Journal of the Chemical Society - Perkin Transactions 1, 1998 , # 18 p. 3065 - 3080

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Citation Number: 28

Abstract

α, β-Diarylvinyl-and α-styryl-carbodiimides, prepared by the aza-Wittig reaction of iminophosphoranes with isocyanates, underwent either 6π-electrocyclisation upon heating or a Diels–Alder reaction under thermal or Lewis acid-promoted conditions with appropriate dienophiles such as tetracyanoethylene, dimethyl acetylenedicarboxylate, maleimide, ethyl propiolate and tosyl isocyanate, to give isoquinolines, pyridines, oxazines, pyrimidines ...