Cumyl hydroperoxide asymmetric epoxidation

Kinetic resolutions. A chiral alcohol is obtained on. selective removal of one enantiomer by acetylation using a chiral analog 1 of DMAP, or by oxidation based on hydrogen transfer to acetone mediated by a Ru complex 2. Benzylic secondary alcohols are resolved by selective pivaloylation with optically activeA-pivaloyl-4-t-butylthiazolidine-2-thione. A kinetic resolution of sulfoxides is based on asymmetric oxidation with (i-PrO)4Ti-cumyl hydroperoxide in the presence of a tartrate ester. Kinetic resolution of 1,3-diarylallenes is realized by selective oxidation with NaClO catalyzed by a chiral (salen)manganese(III) complex, whereas asymmetric hydrolysis of terminal epoxides with the aid of a chiral (salen)cobalt(II) catalyst solves the problem of their accessibility. 

Adam et al. also successfully applied Wynberg s condition to the asymmetric epoxidation of isoflavones [22], Using the chiral PTC 18 and cumyl hydroperoxide (CHP) as an oxidant, the isoflavone epoxide was obtained almost quantitatively and with excellent enantio selectivity (up to 98% ee) even at a low catalyst loading (1 mol%) (Scheme 5.16). 

Sharpless asymmetric epoxidation (chapter 27) of the allylic alcohol 148 with cumyl hydroperoxide and (+)-di-isopropyl tartrate (DIPT) gave the epoxide 149 in excellent yield and enantiomeric purity. The other enantiomer could be made simply by using the other enantiomer of DIPT. The problem is now how to react the epoxide regiospecifically with a nitrogen nucleophile ... 

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