Efficient stereo- and regioselective hydroxylation of alkanes catalysed by a bulky polyoxometalate.
Direct functionalization of alkanes by oxidation of C-H bonds to form alcohols under mild conditions is a challenge for synthetic chemistry. Most alkanes contain a large number of C-H bonds that present difficulties for selectivity, and the oxidants employed often result in overoxidation. Here we describe a divanadium-substituted phosphotungstate that catalyses the stereo- and regioselective hydroxylation of alkanes with hydrogen peroxide as the sole oxidant. Both cyclic and acyclic alkanes were oxidized to form alcohols with greater than 96% selectivity. The bulky polyoxometalate framework of the catalyst results in an unusual selectivity that can lead to the oxidation of secondary rather than the weaker tertiary C-H bonds. The catalyst also avoids wasteful decomposition of the stoichiometric oxidant, which can result in the production of hydroxyl radicals and lead to non-selective oxidation and overoxidation of the desired products.
Kamata
Keigo
K
Department of Applied Chemistry, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan.
Yonehara
Kazuhiro
K
Nakagawa
Yoshinao
Y
Uehara
Kazuhiro
K
Mizuno
Noritaka
N
D000438:Alcohols / Q000378:metabolism*; D000473:Alkanes / Q000737:chemistry*; D006861:Hydrogen Peroxide / Q000737:chemistry*; D006900:Hydroxylation; D008958:Models, Molecular; D016877:Oxidants / Q000737:chemistry*; D010084:Oxidation-Reduction; D013237:Stereoisomerism; D017973:Tungsten Compounds / Q000494:pharmacology*; D000099294:Polyoxometalates
D000438:Alcohols; D000473:Alkanes; D006861:Hydrogen Peroxide; D016877:Oxidants; D017973:Tungsten Compounds; C102296:polyoxometalate I; D000099294:Polyoxometalates