Date : 2014. 3. 20, 4:30 PM Place : Int"l conf. room, Bldg.25-1 -Abstract- The ester moiety represents one of the most ubiquitous functional groups in organic compounds, serving as both key intermediate and protecting group in organic transformations. Among various esterification reactions established so far, one of the most convenient synthetic methods is transesterification, in which methyl or ethyl esters react with various alcohols to give the corresponding esters in one step. We developed μ-oxo-tetranuclear zinc cluster Zn₄(OCOCF₃)₆O as an efficiently catalyst for transesterification, including chemoselective acylation of hydroxy group in the presence of aliphatic amino group, catalytic acetylation of alcohols and catalytic deacetylation of acetates. Because of mildness of the reaction conditions, these reactions have a high degree of functional-group tolerance. Recently, cobalt clusters mediate the same chemoselectivity for transesterification. Amide bond formation and degradation are also discussed.