Reactions Related to Free Radical Intramolecular Additions

Reactions related to Free Radical Intramolecular Additions 

In this section we shall describe some reactions which present many features similar to intramolecular free radical additions, according to the mechanistic probes discussed in the preceding sections. These examples will permit a critical discussion of the use of the free radical intramolecular cycliza-tion probe. 

It is also very interesting to compare the photochemical behavior of 1,6- 

Since Roberts observed the cyclopropylmethyl I-but-3-enyl Grignard reagent rearrangement in I960, the cyclization of unsaturated Grignard 

Other unsaturated organometallics such as those derived from sodium, lithium, aluminum, gallium, indium, zinc, silver, and silyllithium readily give cyclized compounds. Although the cyclization is easier in the Cy5/Cy6 case and gives the (Cy5) compound, a concerted rather than an homolytic pathway is probably involved. Nevertheless, it must be noted that l-methyl-5-hexenylaluminum gives the 1,2-dimethylcyclopentane with a cis/trans ratio of 2.9 1, similar to the free radical cyclization ratio. 

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D. Reactions related to Free Radical Intramolecular Additions... 

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