Dependence of the Reactivities of Titanium Enolates on How They Are Generated: Diastereoselective Coupling of Phenylacetic Acid Esters Using Titanium Tetrachloride
作者:Yoshihiro Matsumura、Maiko Nishimura、Hiroyuki Hiu、Mitsuaki Watanabe、Naoki Kise
DOI:10.1021/jo952204h
日期:1996.1.1
phenylacetic acid esters was easily achieved by treating the esters with TiCl(4) and then adding Et(3)N to the resulting solution. The products consisted of dl- and meso-2,3-diphenylsuccinic acid esters with the Claisen condensation product, and the ratio of these products depended on the reaction conditions. Reaction conditions suitable for high dl selectivity were determined, and a dimer of titanium enolate
通过用TiCl(4)处理酯,然后将Et(3)N添加到所得溶液中,可以轻松实现苯乙酸酯的氧化偶联。产物由dl-和meso-2,3-二苯基丁二酸酯与Claisen缩合产物组成,这些产物的比例取决于反应条件。确定适合于高dl选择性的反应条件,并假定烯醇钛的二聚体作为负责高dl选择性的中间体。将选择性与已知的氧化偶合中的选择性进行比较,在已知的氧化偶合中,烯醇钛中间体是通过烯醇锂和甲硅烷基烯醇醚制备的。结果表明,烯醇钛中间体的反应性取决于其生成方式。