Hypervalent iodine oxidation of 5-substituted and 5-methyl-4-substituted pyrazol-3(2H)-ones. A facile synthesis of 2-alkynoic and 2,3-allenic esters
Abstract
Phl(OAc)2–MeOH causes oxidation of 5-substituted pyrazol-3(2H)-ones to the 2-alkynoic methyl ester and 5-methyl-4-substituted pyrazol-3(2H)-ones to the 2,3-allenic methyl ester.