Metal-catalyzed acyl transfer reactions of enol esters: Role of Y-5((OPr)-Pr-i)(13)O and (thd)(2)Y((OPr)-Pr-i) as transesterification catalysts

[GRAPHICS] Primary and secondary alcohols react with vinyl or isopropenyl acetate at r oom temperature in the presence of catalytic amounts (0.05-1 mol %) of Y5(( OPr)-Pr-i)(13)O to give the corresponding esters. In selected cases, the yt trium catalyst promotes the selective O-acylation of amino alcohols without the formation of the amide. Enol esters also react with a-amino acid ester s in the absence of a catalyst, at room temperature, to give the correspond ing amides.