Orthogonally Protected 1,2-Diols from Electron-Rich Alkenes Using Metal-Free Olefin syn-Dihydroxylation

A new method for the stereoselective metal-free syn-dihydroxylation of electron-rich olefins is reported, involving reaction with TEMPO/IBX in trifluoroethanol (TFE) or hexafluoroisopropanol (HFIP) and the addition of a suitable nucleophile. Orthogonally protected syn 1,2-diols were obtained with high levels of diastereocontrol, and these products were selectively deprotected and selectively functionalized into synthetically useful compounds.