Trimethylsilyl trifltate catalyzed aldol-type reaction of enol silyl ethers and acetals or related compounds
作者:Shizuaki Murata、Masaaki Suzuki、Ryoji Noyori
DOI:10.1016/s0040-4020(01)86671-0
日期:1988.1
condensation of enol trimethylsllyl ethers with acetals, orthoformate, or 2-acetoxytetrahydrofuran or -pyrans to give the corresponding β-alkoxy carbonyl compounds. Reaction of enol silyl ethers and carboxonium triflate ion-pair intermediates occurs via acyclic transition states and exhibits moderate to high erythro selectivity independent of the geometry (E/Z) of the enol silyl ethers.
加入或不加入受阻叔胺的三氟甲磺酸三甲基甲硅烷基酯催化烯醇三甲基甲硅烷基醚与缩醛,原甲酸酯或2-乙酰氧基四氢呋喃或-吡喃的定向缩合,得到相应的β-烷氧基羰基化合物。烯醇甲硅烷基醚与三氟甲磺酸钾离子对中间体的反应通过无环过渡态发生,并且表现出中等至高的赤型选择性,而与烯醇甲硅烷基醚的几何形状(E / Z)无关。