The cycloaddition reaction of N-hydroxysuccinimide ester and isocyanatoacetate catalyzed by copper was described. A series of 4,5-disubstituted oxazole compounds, including ones derived from natural fatty acids, drugs, amino acids, and peptides, were obtained in moderate to high yields. The derivatization reaction was explored. The reaction mechanism was discussed.

A metal-free oxidation reaction of trichloroacetimidates to aldehydes or ketones with DMSO as an oxidant is reported. The reaction exhibits a broad range of functional group tolerance. Detailed mechanistic studies were performed with the aid of NMR, in situ IR spectroscopy, GC-MS analysis and 18 O-labeling experiments. 4 5 6 7 8

A direct and catalytic dehydrative esterification of carboxylic acids with alcohols is described. B(C 6 F 5 ) 3 is shown to be a highly effective catalyst for the Fischer esterification, providing esters in high to excellent yields. This esterification shows excellent chemo-and site-selective monoesterification of various polyols without any protection step, including bio-derived molecule glycerol.

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