PHOSPHORUS COMPOUNDS WITH UNUSUAL COORDINATION - 20. 1,2,3,4-TRIAZAPHOSPHOLES BY -CYCLOADDITION OF AZIDES TO A STABLE PHOSPHAALKYNE

Article abstract of DOI:10.1016/S0040-4020(01)90292-3

The azides 2a-i undergo regiospecific <3+2>-cycloaddition with the phosphaalkyne 1 to form the 1,2,3,4-triazaphospholes 3a-i; in the case of the reaction with 2j, an additional silyl shift occurs resulting in the formation of 4j.The latter product can be hydrolyzed to 6 which has also been prepared independently from 1 and hydrazoic acid (7).Flash vacuum pyrolyses of the 1,2,3,4-triazaphospholes 3c and 3e produce mixtures of the isomers 13a,b and 14a,b, respectively, from which the 1,2-azaphospholes 14 can be isolated as the major reaction products.