Catalytic oxidative cleavage of terminal olefins by metal stearate complexes

Abstract

Selective functionalization of olefins is not only an industrially important process, but also has many synthetic utilities in academic point of view. This work focuses on the development of a new synthetic methodology for the preparation of carbonyl compounds from the oxidative cleavage of terminal olefins using alpha-methylstyrene as a model compound. With the use of TBHP as an oxidant in combination with chromium(III) stearate catalyst, selective oxidation of conjugated double bonds with aromatic ring or carbonyl group was achieved at ambient temperature in 24 hours in moderate to excellent yield. Both the catalyst and TBHP are essential in promoting the reaction. The oxidative cleavage works well in aprotic solvents such as isooctane, acetonitrile, and 1,2-dichloroethane. The optimized condition was accomplishedly applied in the oxidative cleavage of a variety of different terminal olefins. The oxidative cleavage of electron rich alpha-methylstyrene derivatives proceeds in good to excellent yield. Lower yields were observed in alpha-methylstyrene derivatives containing an electron withdrawing group. The oxidative cleavage is selective for electron rich conjugated double bond with aromatic ring or carbonyl group. This developed oxidation reaction was believed to undergo via free radical process and high valent chromium oxo species.