A xerogel-sequestered selenoxide catalyst for brominations with hydrogen peroxide and sodium bromide in an aqueous environment

Stephanie M Bennett; Ying Tang; Danielle McMaster; Frank V Bright; Michael R Detty

doi:10.1021/jo801234e

A xerogel-sequestered selenoxide catalyst for brominations with hydrogen peroxide and sodium bromide in an aqueous environment

J Org Chem. 2008 Sep 5;73(17):6849-52. doi: 10.1021/jo801234e. Epub 2008 Aug 1.

Authors

Stephanie M Bennett¹, Ying Tang, Danielle McMaster, Frank V Bright, Michael R Detty

Affiliation

¹ Department of Chemistry, University at Buffalo, The State University of New York, 627 Natural Sciences Complex, North Campus, Buffalo, New York 14260-3000, USA.

PMID: 18671430
DOI: 10.1021/jo801234e

Abstract

4-(Hydroxymethyl)phenyl benzyl selenoxide (4) sequestered in a halide-permeable, Class II xerogel formed from 10/90 (mol/mol) 3-aminopropyltriethoxysilane/tetraethoxysilane catalyzes the bromination of organic substrates (4-pentenoic acid, 3,5-dihydroxybenzoic acid, 1,3,5-trimethoxybenzene, N-phenylmorpholine, and N,N-dimethylaniline) with NaBr and H2O2. Catalyst performance (reaction rate) when sequestered within the halide-permeable xerogel is 23-fold greater in comparison to xerogel-free catalyst in solution. The catalyst is easily separated from the reaction mixture via filtration and the recovered catalyst can be reused without loss of activity through formation of the first 80 mol of product per mole of catalyst.