| Research Abstract |
(1) Oxidative Desulfurization Fluorination
Upon reaction with an oxidant like a positive halogen, organosulfur compounds gives sulfonium ions whose C-S bonds are weaked to undergo nucleophilic substitution readily. A fluoride ion of 70% HF/Py and Bu_4NH_2F_3 replaces sulfur to give organofluorine compounds. In this way, trifluoromethyl-substituted aromatics and olefins, trifluoromethyl ethers, trifluoromethylamines, alpha-fluoro sulfides, and vis-difluoro olefins are shown to be readily available from the corresponding organosulfur precursors.
(2) Cross-Coupling Reactions with Organosilicon Compounds
This novel reaction is now called as the Hiyama Coupling. Although a trimethylsilyl group is pertinent to vinylsilanes, SiFMe_2 or SiF_2 Me is necessary for alkenylsilanes in general.
Alkoxysilanes also are applicable. As a coupling partner, aryl chlorides are now shown to be applicable.
Transmetalation from silicon to copper(I) is now achieved in DMF.Thus, alkynylsilanes couple with halobenzenes or dimerizes oxidatively using a palladium catalyst. Conjugate reduction of alpha, beta-unsaturated esters and ketones is attained with hydrosilanes.
(3) Cross-Coupling and Carbostannylation with Organotin Compounds
Using a novel catalyst consisting of palladium and an imino phosphine ligand, organotin compounds are shown to readily undergo cross-coupling reactions, oxidative dimerization, and carbostannylation to acetylenes.
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