Direct Conversion of Esters to Secondary Amides Using Tin(II) Reagents.

Abstract We have developed two new procedures for the direct conversion of esters to secondary amides. In our first procedure, secondary amides can be prepared in 83–98% yield starting from glycol esters. Addition of Sn[N(TMS) 2 ] 2 and a primary amine to the glycol ester generates an intermediate tin(II) alkoxy amide, which delivers the amino group intramolecularly to give the amide. A second general procedure for the preparation of secondary amides start with methyl esters. Treatment of methyl ester with a tin reagent derived from Sn[N(TMS) 2 ] 2 , Me 2 NCH 2 CH 2 OH, and a primary amides in 87–98% yield.