Carbonate, acetate and phenolate phosphonium salts as catalysts in transesterification reactions for the synthesis of non-symmetric dialkyl carbonates
作者:Maurizio Selva、Marco Noè、Alvise Perosa、Marina Gottardo
DOI:10.1039/c2ob25447f
日期:——
MeOCO2; HOCO2; AcO; PhO were excellent organocatalysts for the transesterification of dimethyl and diethyl carbonate with primary and secondary alcohols, including benzyl alcohol, cyclopentanol, cyclohexanol, and the rather sterically hindered menthol. Conditions were optimized to operate with very low catalyst loadings up to 1 mol% and to obtain non-symmetric dialkyl carbonates (ROCO2R′; R = Me, Et)
甲基三辛基phosph甲基碳酸酯[P 8881 ] + [MeOCO 2 ] -通过烷基的烷基化反应制得。三辛基膦与无毒的碳酸二甲酯。这种盐是合成不同离子液体的方便来源,其中甲基三辛基phosph阳离子与弱碱性阴离子(如碳酸氢根,乙酸根和酚酸根)偶联。在90-220℃下,所有这些化合物[P 8881 ] + X - ; X = MeOCO 2;HOCO 2 ; AcO; PhO是出色的有机催化剂,可用于碳酸二甲酯和碳酸二乙酯与伯醇和仲醇的酯交换反应,包括苯甲醇, 环戊醇, 环己醇,而且在空间上受阻 薄荷脑。优化条件以在高达1 mol%的极低催化剂负载下运行,并获得选择性高达99%且分离产率> 90%的非对称碳酸二烷基酯(ROCO 2 R'; R = Me,Et)。通过同时活化亲电子和亲核反应物的协同机理,对所研究的离子液体的催化性能进行了讨论。