A rapid and high-yielding silylation of terminal alkynes employing TMSOTf and catalytic quantities of Zn(OTf)(2) has been developed. The reaction works well for a variety of substrates including reactive esters. Fifteen examples with yields of > 90% are reported.
Two kinds of electronic factors have been clarified to control the reactivity in alkynylation of glycals with silylacetylenes. One is that the reactivity of nucleophile silylpropargyl alcohol derivative largely depends on the protecting group. The second factor is found in the similar electrophiles as oxocarbenium intermediates that were generated from glucals or galactals. Diminished reactivity was found with the 4-axial substituents such as acetoxy or methoxy group.
A unique type of platinum catalysis that is valuable for the synthesis of α,β-unsaturatedketones is described. In the presence of PtCl2, (2-arylethynyl)trimethylsilanes reacted with H2O at 30 °C to give 1,4-diarylbut-3-en-2-ones in moderate to good yields. (2-Alkylethynyl)trimethylsilanes could be efficiently converted into the corresponding hydrative dimerization products by a modified Pt catalyst
描述了一种对 α,β-不饱和酮的合成有价值的独特类型的铂催化。在 PtCl 2存在下,(2-芳基乙炔基)三甲基硅烷与 H 2 O 在 30 °C 下反应,以中等至良好的收率得到 1,4-二芳基丁-3-en-2-酮。 (2-烷基乙炔基)三甲基硅烷可以通过改性Pt催化剂体系有效转化为相应的水合二聚产物。机理研究表明酰基铂中间体参与催化循环。