Direct and indirect electrochemical generation of alkoxycarbenium ion pools from thioacetals
作者:Kouichi Matsumoto、Koji Ueoka、Shinkiti Suzuki、Seiji Suga、Jun-ichi Yoshida
DOI:10.1016/j.tet.2009.09.020
日期:2009.12
Thioacetals were found to be effective precursors to generate and accumulate alkoxycarbeniumions based on direct and indirect cation pool methods. Alkoxycarbeniumions thus generated reacted with carbonnucleophiles such as allylsilanes and enol silyl ethers to give C–C bond formation products in good yields.
Electrochemical Oxidation of 1-Phenylthio-1-trimethylsilylalkanes
作者:Jun-ichi Yoshida、Sachihiko Isoe
DOI:10.1246/cl.1987.631
日期:1987.4.5
Electrochemical oxidation of 1-phenylthio-1-trimethylsilylalkanes in the presence of alcohol resulted in facile cleavage of the carbon–silicon bond and formation of the corresponding acetals.
在醇存在下,1-苯硫基-1-三甲基硅基烷的电化学氧化导致碳-硅键的容易断裂,并形成相应的缩醛。
Indirect Cation-Flow Method: Flash Generation of Alkoxycarbenium Ions and Studies on the Stability of Glycosyl Cations
作者:Kodai Saito、Koji Ueoka、Kouichi Matsumoto、Seiji Suga、Toshiki Nokami、Jun-ichi Yoshida
DOI:10.1002/anie.201100854
日期:2011.5.23
Go with the flow: The indirect cation‐flow method based on the generation of highly reactive organic cations from their precursors using electrochemically generated [ArS(ArSSAr)]+ was developed in flow microreactor systems (see scheme; Bn=benzyl, M=micromixer, R=microtube reactor). The method was applied to evaluate glycosyl cations such as A or their equivalents and glycosylation reactions.
Monothioacetals are obtained by treating the corresponding acetals with organotin thiophenoxides in the presence of BF2·OEt2. The reaction proceeds under mild conditions to provide the desired compounds with high selectivity.
Methoxy(phenylthio)methane undergoes electrophilic alkylation followed by nucleophilic allylation or propargylation which is dramatically changed depending on the Lewis acid employed providing a methoxy- or phenylthiomethylene 1,1-dipole synthon.