Synthesis of trimethylsilyl carboxylates by HMDS under solvent-free conditions
作者:Marjan Jereb、Janja Lakner
DOI:10.1016/j.tet.2016.08.003
日期:2016.9
carboxylic acids were transformed into their trimethylsilyl esters with HMDS in a practically completely solvent-free process, while a catalytic amount of iodine was required in some cases. The process has several advantages over the known methods: untreated reactants, air atmosphere, mild and neutral conditions, no evolution of hydrogen halide, no need of an additional base, low amount of waste, completely
In the presence of a catalytic amount of Lewis acid, various carboxylic esters or S-phenyl carbothioates are prepared in excellent yields by the respective reactions of equimolar amounts of silyl carboxylates and alkyl silyl ethers or phenyl silyl sulfides with 4-trifluoromethylbenzoic anhydride.
An Efficient Catalytic Friedel-Crafts Acylation Reaction of Equimolar Amounts of Aromatic Compounds and Free Carboxylic Acids or Their Trimethylsilylesters via Mixed Anhydrides
作者:Teruaki Mukaiyama、Kaoru Suzuki
DOI:10.1246/cl.1992.1751
日期:1992.9
In the presence of an active catalyst generated from SiCl4 and AgClO4, the Friedel-Crafts acylation reaction between equimolar amounts of aromatic compounds and mixed anhydrides, formed in situ from free carboxylic acids (or their trimethylsilylesters) and p-trifluoromethylbenzoic anhydride, smoothly proceeds at room temperature to afford the corresponding aromatic ketones in high yields.
Treatment of trimethylsilyl esters with a reagent for alkylidenation of carbonyl groups derived from 1,1-dibromoalkane, zinc, TiCl4, and TMEDA in THF gives Z-trimethylsilyl enol ethers in a regio- and stereoselective manner.