已经开发了两种合成乙烯酮烷基三烷基甲硅烷基缩醛(I)的通用方法。第一种通过二取代的丙二酸酯与钠/二甲苯的反应,另一种方法是通过使取代的乙酸酯的α-阴离子与三甲基氯硅烷反应。还制备了碳甲氧基乙烯酮甲基三甲基甲硅烷基乙缩醛(III)。二芳基乙烯酮甲基三甲基甲硅烷基乙缩醛的热解以良好的收率得到二芳基乙烯酮。该反应的机理已被确立为分子内采用18 O.烷基,芳基和二烷基烯酮methyltrimethylsilyl缩醛热解,得到烯酮烯酮缩醛加成化合物(II)。芳基烯缩醛(I)的光谱研究与偶极结构Ar 2 C -- C +一致(OMe)OSiMe 3。得出的一般结论是,围绕碳bond碳双键的旋转自由度由连接的取代基决定。光谱研究与其中甲氧甲氧基和三甲基甲硅烷基氧基为顺式的化合物(III)的通量行为一致。乙烯酮缩醛(I)大量断裂的结果与它们的热裂解相似。有趣的是,质谱仪中的乙烯酮-乙烯酮缩醛(II)被分解
The addition of Grignardreagents to ketones is significantly enhanced by cerium chloride with remarkable suppression of side reactions, particularly enolization. Some esters, which are prone to side reactions, also react readily with Grignardreagents in the presence of cerium chloride to give normal reaction products in reasonable to high yields.
Dependence of the Reactivities of Titanium Enolates on How They Are Generated: Diastereoselective Coupling of Phenylacetic Acid Esters Using Titanium Tetrachloride
phenylacetic acidesters 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 acidesters 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
USE OFCERIUM(III) CHLORIDE IN THE REACTIONS OF CARBONYL COMPOUNDS WITH ORGANOLITHIUMS OR GRIGNARD REAGENTS FOR THE SUPPRESSION OF ABNORMAL REACTIONS:1-BUTYL-1,2,3,4-TETRAHYDRO-1-NAPHTHOL