Preparation by Addition to Unsaturated Substrates

By Addition to Unsaturated Substrates. Bromo- and iodo-functionalization of alkenes using a combination of the halogen and a mercury(II) salt has enabled the preparation of a series of 1,2-disubstituted products in which the second substituent, derived from the mercury salt, may be another halide or a series of other groups including esters, nitrate, thiocyanide, or a sulphone. Stereoselective bromination of acetylenes to furnish 

Reagents i, (CF3S02)20, Na2C03 CH2CI2 ii, Mgl2, Et N, CS2 or CgHg, reflux 

2-dibromoalkenes has been demonstrated using tetrabutylammonium tribromide, the high product stereoselectivity being rationalized by 

6-bromovinyl ketones from the corresponding acetylenic ketones has 

Other reagents which have been found to promote the same conversion 

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