Sulfated polyborate-catalyzed N-formylation of amines: a rapid, green and efficient protocol

A rapid, green and efficient method for N-formylation reaction of various amines with formic acid in the presence of sulfated polyborate catalyst under solvent-free conditions has been described. The catalyst has the advantage of mild Bronsted as well as Lewis acid character. The catalyst is recyclable with no significant loss in catalytic activity. The present protocol is advantageous due to its solvent-free condition, short reaction time, high yields, easy workup and ability to tolerate a variety of functional groups.