A new conjugated addition of trialkyl phosphites and alkylidenephosphoranes to 3-ω-azideoacetyl coumarin synthesis of some 1,2,3,4-triazaphospholes, triazoles, and azido-coumarin derivatives

摘要

A new and efficient conjugate addition of trimethyl and triethyl phosphites to 3-ω-azidoacetylcoumarin (1) has been studied. The reaction proceeded smoothly at r.t. furnishing 1,2,3,4-triazaphosphole coumarin derivatives 4a,b in ～75% yields. Linear substituted triazoles 10a,b were also obtained from the reactions of 1 with α-keto ylides, acetyl-and benzoylmethylene triphenylphosphoranes. Contrary to these results, Wittig reaction was occurred when 1 was allowed to react with α-alkoxycarbonylmethylene-and cyanomethylenetriphenylphosphoranes 7c-e as well as with methylidene-and benzylidenetriphenylphosphoranes 8a,b resulting in the formation of the corresponding olefins either as an intermediate 14b or as final products 11a-c.