Mild Conversion of Esters LackingAcidic α-Hydrogens into Amides via Samarium(III)Tris[hexamethyldisilazide] and Amines

Samarium(III) tris[hexamethyldisilazide] (Sm[(Me 3 Si) 2 N] 3 = Sm[HMDS] 3 )promotes the direct conversion of an ester admixed with an amineinto the corresponding carboxamide under exceptionally mild conditions(≤0 ˚C) and in high yields. Only a slightexcess of amine and the lanthanide complex are required to effect completeconversion of the ester into the amide. Esters with acidic α-hydrogensundergo a competing Claisen-like condensation along with the desiredconversion into amides.