either carboxylic acids or alcohols are normally needed. We found that the directcondensation of equimolar amounts of carboxylic acids and alcohols could be achieved using hafnium(IV) or zirconium(IV) salts. These metal salts are highly effective as catalysts for the selective esterification of primary alcohols with carboxylic acids in the presence of secondary alcohols or aromatic alcohols. The present
N-Butyl-2,4-dinitro-anilinium p-toluenesulfonate (1) was found to be a very active esterification catalyst that promotes condensation of equal mole amount of carboxylic acids and alcohols under mild conditions. This catalyst is also highlyselective towards carboxylic acid and alcohol substrates at ambient temperature.
发现 N -Butyl-2,4-dinitro-anilinium p-甲苯磺酸盐( 1 ) 是一种非常活跃的酯化催化剂,可在温和条件下促进等摩尔量的羧酸和醇的缩合。该催化剂在环境温度下对羧酸和醇底物也具有高度选择性。
Bulky diarylammonium arenesulfonates as mild and extremely active dehydrative ester condensation catalysts
作者:Akira Sakakura、Shoko Nakagawa、Kazuaki Ishihara
DOI:10.1016/j.tet.2005.09.059
日期:2006.1
especially large-scale, fundamental reactions like estercondensations, are highly desirable for many reactions. Bulky diarylammonium pentafluorobenzenesulfonates and tosylates serve as extremely active dehydration catalysts for the estercondensation reaction of carboxylicacids with equimolaramounts of sterically demanding alcohols and acid-sensitive alcohols. Typically, the esterification reaction is performed
Estercondensation is one among the most fundamental organic transformations, and more environmentally benign alternatives to current esterification processes are needed. Under solvent-free and drying agent-free conditions, catalytic amounts of sulfonic acids promote estercondensationbetween an equimolar mixture of carboxylicacids and alcohols. In particular, p-toluenesulfonic acid (TsOH) and 10-camphorsulfonic
Zincperchloratehexahydrate, Zn(ClO4)2⋅6H2O, efficientlycatalyses the esterification between nearly equimolar amounts of carboxylicacids and alcohols. The reaction works under solvent-free conditions at relatively low temperatures. Excellent results were obtained with a wide range of substrates.