Free radical-mediated alkylation of general alkenes is a challenging and largely unmet goal. Herein, we disclose a conceptually novel "polarity umpolung" strategy for radical alkylation of alkenes using a portfolio of easily-accessed, dual-function alkylating reagents. This is achieved by substituting inherently nucleophilic alkyl radicals with electrophilic sulfone-decorated surrogates, thus inverting
Evaluation of β- and γ-Effects of Group 14 Elements Using Intramolecular Competition
作者:Masanobu Sugawara、Jun-ichi Yoshida
DOI:10.1021/jo991977t
日期:2000.5.1
gamma-elimination of tin is faster than the beta-elimination of silicon, but slower than the beta-elimination of germanium and tin. The theoretical studies using ab initio molecular orbital calculations of the carbocation intermediates are consistent with the experimental results. The effect of substituents on silicon was also studied. The introduction of sterically demanding substituents on silicon disfavored
A radical-mediated monofluoroalkylativealkynylation of alkenes is disclosed for the first time. The reaction demonstrates a remarkably broad substrate scope in which both activated and unactivated alkenes are suitable starting materials. The concurrent addition of an alkynyl and a monofluoroalkyl group onto an alkene proceeds through a docking-migration sequence, affording a vast array of valuable
Crucial role of the ligand of silyl Lewis acid in the Mukaiyama aldol reactionElectronic supplementary information (ESI) available: experimental section. See http://www.rsc.org/suppdata/cc/b2/b203838b/
The Me3SiX-induced Mukaiyamaaldolreaction proceeds through each catalytic cycle under the influence of X-: the silyl group of Me3SiNTf2 does not release from -NTf2 and that of silyl enol ether intermolecularly transfers to the product, while the silyl group of Me3SiOTf remains in the product and that of the silyl enol ether becomes the catalyst for the next catalytic cycle.
PROTECTION OF ALCOHOLS AND ACIDS WITH ALLYLSILANES CATALYZED BY IODINE OR IODOTRIMETHYLSILANE IN CHLORINATED HYDROCARBON
作者:Akira Hosomi、Hideki Sakurai
DOI:10.1246/cl.1981.85
日期:1981.1.5
Many triorganosilyl ethers and esters were prepared by the reaction of allylsilanes with alcohols catalyzed by iodine or iodotrimethylsilane in excellent yields. Bromine and bromotrimethylsilane were also effective catalysts.