Formation of five-membered rings - 1,3-dipolar cycloaddition reactions

3 Formation of five-membered rings - 1,3-dipolar cycloaddition reactions 

A number of 1,3-dipolar cycloadditions to fluoroaUcenes have been reported [245] some examples are listed in Table 7.15. 

Addition of diazomethane to fluoroalkenes [72] follows the order of reactivity (Rf)2C=C(Rf)2 (Rf)2C=CFRf (Rf)2C=CF2, RfCF=CFRf(Rf = perfluoroalkyl). In reactions involving unsymmetrical fluoroalkenes the additions are highly regiospecific, with the carbon atom of the dipole becoming attached to the site most susceptible 

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