Organocatalytic epoxidation and allylic oxidation of alkenes by molecular oxygen
作者:Marina Petsi、Maria Orfanidou、Alexandros L. Zografos
DOI:10.1039/d1gc03029a
日期:——
reduction of dioxygen by Hantzsch ester under mild conditions to allow the aerobic metal-free epoxidation of electron-rich alkenes. Mechanistic crossovers are underlined, explaining the dual role of Hantzsch ester as a reductant/promoter of the DKP catalyst and a simultaneous competitor for the epoxidation of alkenes when HFIP is used as a solvent. Expansion of this protocol to the synthesis of allylic alcohols
(+)-Humulenol-II, a minor component of the volatile oil from the rhizomes of Zingiber zerumbet, is shown to possess the absolute stereostructure I and has been directly correlated with (−)-humulene epoxide-II. The preparation of (+)-humulenol-I is also described.