Widely Useful DMAP-Catalyzed Esterification under Auxiliary Base- and Solvent-Free Conditions
作者:Akira Sakakura、Kimio Kawajiri、Takuro Ohkubo、Yuji Kosugi、Kazuaki Ishihara
DOI:10.1021/ja075824w
日期:2007.11.28
catalytic condensation of carboxylic acids with equimolar amounts of alcohols is the most desirable. Although several highly active dehydration catalysts have been reported, more efficient alternatives are still strongly needed because the dehydrative esterification of tertiary alcohols, phenols, acid-sensitive alcohols, amino acids, and hardly soluble alcohols has never proceeded satisfactorily. Here
关于原子经济性和 E 因子,羧酸与等摩尔量的醇的催化缩合是最理想的。尽管已经报道了几种高活性脱水催化剂,但仍然强烈需要更有效的替代品,因为叔醇、酚、酸敏感醇、氨基酸和难溶性醇的脱水酯化从未令人满意地进行。在这里,我们报告了对经典 DMAP 催化醇酰化的新见解:令人惊讶的是,仅 0.05-2 mol% 的 DMAP 就可以在无碱和无溶剂的辅助条件下有效地促进醇与酸酐的酰化,从而得到相应的酯高产量。此外,我们在不使用任何溶剂的情况下实现了市售聚苯乙烯支持的 DMAP 的回收和再利用。这些偶然发现提供了广泛有用且环境友好的酯化方法,这可能比催化脱水缩合方法更实用和可靠,特别是对于几乎不与羧酸直接缩合的反应性较低的醇。