Dimethyl sulfoxide bromohydrin formation

In practice, few alkenes are soluble in water, and bromohydrin formation is often carried out in a solvent such as aqueous dimethyl sulfoxide, CH3SOCFI3 (DMSO), using a reagent called W-brornosuccinimide ( rBS) as a source of Br2. NBS is a stable, easily handled compound that slowly decomposes in water to yield Br2 at a controlled rate. Bromine itself can also be used... 

Halohydrin formation with subsequent reductive dehalogcnation represents an interesting variation on the theme. For example, when the enone rac-1 was treated with A -bromosuccin-imide in aqueous dimethyl sulfoxide, the bromohydrin roc-2 was formed, predominantly as one diastereomer (the relative configuration at C-3 was not established)23. Reduction with tri-butyltin hydride gave the diastereomeric products exo-3 and endo-3 in 27% and 63% yield, respectively. Here, the product distribution can be explained by the preferred attack of the hydride reagent on the exo-face of the intermediate bicyclic carbon radical, i.e., by kinetic control. Thus, the predominant endo-orientation of the 2-(2-hydroxypropyl) substituent at C-3 was achieved, in contrast to what may be expected from a reversible, i.e., thermodynamically controlled, hydration of the enone rac-1. 

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See also in sourсe #XX -- [ ]

See also in sourсe #XX -- [ ]

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