Catalytic oxyalkylation of alkenes with alkanes and molecular oxygen via a radical process using N-hydroxyphthalimide.

Abstract

A novel catalytic method for the radical addition of alkanes and molecular oxygen to electron-deficient alkenes was achieved by the use of N-hydroxyphthalimide (NHPI) combined with a Co species as the catalyst. This reaction is referred to as oxyalkylation of alkenes with alkanes and O(2). For instance, the reaction of 1,3-dimethyladamantane with methyl acrylate under molecular oxygen in the presence of catalytic amounts of NHPI and Co(acac)(3) at 70 degrees C for 16 h gave oxyalkylated products in 91% yield. Other alkenes such as fumarate and acrylonitrile also serve as good acceptors of alkyl radicals and O(2) to afford the corresponding adducts in high yields. The generality of the present reaction was examined between various alkanes and alkenes under dioxygen. The behavior of Co ions during the reaction course was discussed. The present reaction involves (i) an alkyl radical generation via hydrogen abstraction of alkane by phthalimide N-oxyl generated in situ from NHPI and O(2) assisted by Co(II), (ii) the addition of the resulting alkyl radical to an electron-deficient alkene to form an adduct radical, (iii) trapping of the adduct radical by O(2) yielding a hydroperoxide, and (iv) the decomposition of the hydroperoxide by Co ions to form an adduct in which a hydroxy or a carbonyl function is incorporated.