A rapid and mild esterification method using carboxylic 2,4,6-trichlorobenzoic anhydrides in the presence of 4-dimethylaminopyridine was developed. The method was also successfully applied to the synthesis of large-ring lactones, including Dl-2,4,6-tridemethyl-3-deoxymethynolide.

The conjugate addition of alcohols to α,β-unsaturated alkynic acid esters proceeds under neutral conditions in the presence of a catalytic amount of trialkylphosphine to give the corresponding β-alkoxy-α,β-unsaturated alkenic acid esters in good to excellent yields.

A remarkable effect of HMPA was observed in the reduction of organic halides with a SmI2-THF solution. Various types of organic halides were reduced rapidly to the corresponding alkanes in almost quantitative yields under mild reaction conditions.

No abstract

The aim of this tutorial review is to highlight the potential application of N-heterocyclic carbenes (NHC) in heterogeneous catalysis. The unique combination of the high reactivity of NHCs together with the ease of separation, purification and recyclability of the solid catalyst makes the heterogeneous system one of the most promising strategies for the synthesis of fine chemicals on an industrial scale. This tutorial review focuses on the most representative examples of this nascent research area and highlights recent achievements of NHCs in heterogeneous catalysis (other than metathesis reactions).We hope this serves as inspiration for further progress in this field.