Halomethanes radical addition reactions

There are examples of other halomethanes that can undergo radical addition. a-Haloesters have been successfully added to alkenes in the presence of copper metal. The copper serves as an electron transfer initiator. The 7-haloester adduct cyclizes to a lactone. The reaction works best when Nal is also used to convert the bromide to the more reactive iodide. " ... 

One of the older preparative free-radical reactions is the addition of polyhalomethanes to alkenes. Examples of addition of carbon tetrabromide, carbon tetrachloride, and bromoform have been recorded. The reactions are chain processes that depend on facile abstraction of halogen or hydrogen from the halomethane ... 

For n = 1, this is the standard synthesis of [l.l.l]propellane 40a.20,21 Also for n = 3, this method makes [3.1.1]propellane 40c accessible with reasonable effort.22 Although [2.1.1]propellane 40b was detected by its IR spectrum at liquid nitrogen temperature,23 it could not be obtained as a stable compound via this route.22 The addition of halomethanes across the central bond by a radical chain mechanism is common to 40a and 40c. The addition of carbon tetrabromide to 40c afforded a 45% yield of 41.18 Likewise, a number of bicy-clo[l.l.l]pentane derivatives 42 were obtained by reaction of the corresponding halomethanes with 40a.17,24... 

One of the older preparative free-radical reactions is the addition of poly-halomethanes to alkenes. Examples of addition of carbon tetrabromide, carbon... 

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