tert-butyl hydroperoxide (TBHP): A versatile oxidizing agent in organic synthesis

Abstract

(A) TBHP is widely used as an epoxidizing agent, both synthetically and industrially. TBHP has been used to effect regiospecific, stereospecific, and asymmetric epoxidations. 8 Zhang and Yamamoto showed that asymmetric epoxidation of allylic alcohols can be carried out using TBHP with a vanadium catalyst and 95% ee was obtained. 9 (B) Styrene can be epoxidized by TBHP to styrene oxide with high selectivity and in high yield using barium oxide (with or without gallium oxide support) as a simple, inexpensive and reusable solid catalyst. 10 trans-Stilbene can be epoxidized by TBHP using a Au/TiO 2 catalyst. 11 (C) The epoxidation of α,β-unsaturated ketone and aldehyde compounds is accomplished by TBHP in the presence of catalytic amounts of Ti(Oi-Pr) 4 or diaryl-2-pyrrolidinemethanols. 12 The epoxides have been obtained in good yields and with ee values of 80-90%. 13 (D) Manganese(III) acetate catalyzed allylic oxidation of alkenes to the corresponding enones was investigated and showed excellent regioselectivity. 14 Some new strategies have been reported for a useful transformation of the allylic oxidation of alkenes to carbonyl compounds, such as the protocols using TBHP catalyzed by transition-metal ion centers (Cr, Ru, Cu, Co, Pd). 15 (E) The palladium-catalyzed allylic alkylation (the Trost-Tsuji reaction) is one of the most important reactions for constructing C-C bonds in modern organic synthesis. Recently, Chao-Jun Li and co-workers found that when a catalytic amount of CuBr and a stoichiometric amount of TBHP were used the desired product was obtained in higher yield. 16 (F) In the presence of a catalytic amount of CuI and inorganic bases such as NaHCO 3, the aldehydes with amine hydrochloride salts gave the amide under mild conditions in good yield. The method can be used as the strategy for amide bond formation. 17 (G) Oxidative cleavage of the C=C bond to afford ketone or aldehyde products with TBHP as the oxidant can be catalyzed by AuCl. This oxidation reaction proceeds under mild conditions in water, a variety of functional groups are tolerated. 18 (H) Copper-catalyzed oxidative esterification of aldehydes with β-dicarbonyl compounds was developed using TBHP as an oxidant. In general, the enol esters were synthesized in good yields (up to 87%) and high stereoselectivity under the optimized reaction conditions. 19. © Georg Thieme Verlag Stuttgart.