Thiocarbonyl compounds coupling reactions

The main problem is how to generate free radicals at low temperatures. It was discovered this can be done by using the trialkylborane-oxygen redox couple. Prior to the studies on thiocarbonyl compounds, Furukawa and Tsuruta (68) had used a mixture of trialkylboranes and oxygen for vinyl polymerizations, and studies by Fordham and Sturm (69) and Zutty and Welch (70) had confirmed them as free-radical polymerizations. For the fluorothiocarbonyl work (39), it was shown that at - 78° C the reaction of a trialkylborane and oxygen proceeds cleanly to an alkylperoxydialkylborane, V. 

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