Metal-catalyzed asymmetric oxidation mediated by optically pure furyl hydroperoxides

Metal-catalyzed asymmetric oxidations which rely on the use of commercially available t-butyl (TBHP) or cumyl hydroperoxides (CHP) and enantiopure ligands represent the majority of protocols reported to obtain enantiomerically enriched valuable compounds such as epoxides, sulfoxides, diols, etc. Herein, we review our recent results on the complementary and less studied oxidative approach based on the use of optically pure alkyl hydroperoxides as oxygen and chirality source. The synthetic sequence to enantiopure furyl hydroperoxides, easily accessible from ketones of the chiral pool is firstly described. Examples of metal-catalyzed asymmetric oxidations using these compounds for the production of enantiomerically enriched sulfoxides and epoxy alcohols are shown. The entire protocol is made more advantageous by recovering the optically pure alcohols during the purification procedure and recycling them for the one-step synthesis of the hydroperoxides

Synthesis of a benzo[b]furyl (+)-Norcamphor-derived hydroperoxide: study of the activity as an oxidant in asymmetric epoxidations

Starting from easily available (+)-norcamphor and according to an established approach, the 2-benzo[b]furyl hydroperoxide exo-5 was obtained in 58% overall yield. In order to ascertain the impact of the modification on the activity of this chiral oxidant, a study was carried out employing it in the asymmetric epoxidation of an allylic alcohol and alpha,beta-enones