Enol formates: ruthenium catalysed formation and formylating reagents

Abstract

The one-step synthesis of the enol formates, isopropenyl, hex-1-en-2-yl, and α-methylenebenzyl formates, directly from terminal alkynes and formic acid with arene–ruthenium(II) catalysts is reported. They have been shown to be effective formylating reagents, under mild and neutral conditions, to produce formamides from primary and secondary amines, formylamino esters, and in the presence of a catalytic amount of imidazole, formates from alcohols or phenols.