REGIOSELECTIVITY IN THE 1,3-DIPOLAR CYCLOADDITION REACTIONS OF NITRILE OXIDES AND ORGANIC AZIDES WITH BROMOCARBAZOLE-1,4-DIONES

摘要

The effect exerted by the presence of a bromine atom in 2 or 3 position of a carbazole-l,4-dione on the regiocontrol of 1,3-dipolar cycloaddition reactions with nitrile oxides and organic azides was investigated. Comparison with the results obtained with 2,3-unsubstituted-carbazole-l,4-dione shows that bromine substituents on para-carbazolequinones effectively orient the 1,3-dipolar cycloadditions. The regiochemistry observed may be explained by the orienting effect of the bromine atom independently of the values of the orbital coefficients.