SeO<sub>2</sub>-Mediated Oxidative Transposition of Pauson–Khand Products
作者:Sara E. Dibrell、Michael R. Maser、Sarah E. Reisman
DOI:10.1021/jacs.9b13818
日期:2020.4.8
Oxidative transpositions of bicyclic cyclopentenones mediated by selenium dioxide (SeO2) are disclosed. Treatment of Pauson-Khand reaction (PKR) products with SeO2 in the presence or absence of water furnishes di- and trioxidized cyclopentenones, respectively. Mechanistic investigations reveal multiple competing oxidation pathways that depend on substrate identity and water concentration. Functionalization
2 + 1] cycloaddition takes place in the rhodium-catalyzed reaction of 1,6-enynes with borylsilanes bearing an alkoxy group on the silicon atoms, which react as synthetic equivalents of silylene. The reaction proceeds efficiently in 1,2-dichloroethane at 80–110 °C in the presence of a rhodium catalyst bearing bis(diphenylphosphino)methane (DPPM) as a ligand to afford 1-silacyclopent-2-enes in good to