Benzyl 4-bromobenzyl sulfoxide

OXIDATION OF BENZYL 4-BROMOBENZYL SULffiDE TO BENZYL 4-BROMOBENZYL SULFOXIDE USING H2O2 IN THE PRESENCE OF ZIRCONIUM TETRACHLORIDE... 

The reaction mixture was extracted with chloroform (4 x lOmL) and the extract dried with anhydrous MgS04. The filtrate was evaporated and benzyl 4-bromobenzyl sulfoxide was obtained as the only product (0.598 g, 96 % yield) (Table 9.2). m.p 139-140 °C. 

Bromination of (-)-(5 )-benzyl methyl sulfoxide 34 with bromine in pyridine affords a mixture of two regioisomers a-bromomethyl benzyl sulfoxide 328 and a-bromobenzyl methyl sulfoxide 329, in a molar ratio of 3 2 (325). Oxidation of thp latter gives the corresponding sulfone (-)-(S)-330, the absolute configuration of which was determined by X-ray analysis. In this context, it is interesting to point out that the formation of the sulfoxide 328 is accompanied by retention at sulfur, whereas 329 is formed with inversion at sulfur. 

A soln. of bromine in dichloromethane and N-bromosuccinimide added at 0° to a stirred soln. of dibenzyl sulfoxide and pyridine in the same solvent, and the product isolated after 0.5 hr. benzyl a-bromobenzyl sulfoxide. Y 85%. -Either brominating agent alone gives lower yields. F. e. s. S. Iriuchijima and G. Tsuchihashi, Synthesis 1970, 588 a-chlorosulfoxides by 1 -chlorobenzotriazole/ pyridine, also with retention of a-deuterium, s. M. Cinquini and S. Colonna, Synthesis 1972, 259. 

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