Tetrahedron

Some novel aspects of regioselectivity in 1, 3 dipolar cycloadditions of 4h-1-benzopyran-4-thione

AK Baruah, D Prajapati, J Sandhu

文献索引：Baruah, Arpan K.; Prajapati, Dipak; Sandhu, Jagir S. Tetrahedron, 1988 , vol. 44, # 19 p. 6137 - 6142

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被引用次数: 23

摘要

4H-1-Benzopyran-4--thio) ie (1) reacted smoothly with nitrilimines (3a-e) to afford regioselectiue cycloadducts (4a-X) in good yields. In contrast, benzonitrile oxide (6) and aldonitrones (7a-d) reacted preferentially at the thione function. The unstable cycloadduct (B) or (9) ruptured to give as isolable products chromone (10) and phenyl isothiocyanate (11) and the tnioamides (12a-d). This indirectly proves the site of attack of the dipole at the ...