This thread is for facile methods of dihalogenation. That means do NOT suggest the handling of elemental chlorine or bromine. Also, exotic reagents or catalysts are out.

The two starting methods are primarily or exclusively bromination reactions.

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In this first paper, CuX2 is complexed with a ligand (don't worry, "a ligand" is one of various, certain, common solvents like acetonitrile or THF), which aids in its otherwise thermally driven decomposition to CuX + (1/2)X2.

William C. Baird, Jr., John H. Surridge, and Maris Buza
Halogenation with copper(II) halides. Halogenation of olefins with complexed copper(II) halides
J. Org. Chem. 1971, 36(22):3324-3330







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In this second paper, an n-bromoamide is used as a the bromine source. I wonder whether a microwave would assist with the low percent conversion of styene or cyclohexene?

Li-Xiong Shao, Min Shi
N-Bromosuccinimide and Lithium Bromide: An Efficient Combination for the Dibromination of Carbon-Carbon Unsaturated Bonds
Synlett 2006(8):1269-1271 DOI: 10.1055/s-2006-941558
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Keywords: dichlorination, dibromination, olefin, pi