Cycloaddition of diazoalkanes to C—N bonds and relevant reactions

The [3 + 2] cycloaddition of diazo compounds to imines or nitriles is an alternative approach to the preparation of 1,2,3-triazoles and 1,2,3-triazolines. For reviews, see CHEC-I 84CHEC-I(5)7I7 . 

The reactions of 3-diazobenzo[6]thiophene-2-one (780) with enaminones leads to the formation of 1,2,3-triazoles (781) (19-77%) as the major products along with by-products (782) (Equation (74)). The nitro derivatives (783) react with various enaminones to give generally good yields of 1,2,3-triazoles (55-82%). The mechanism for the formation of the triazoles is described 93JOC7079 . 

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