Exocyclic -benzyl shift

Computational studies of the cascade rearrangements of the cubylcarbinyl radical have been reported. There is evidence for a free-radical pathway under kinetic entropy control for an exocyclic [l,3]-benzyl shift observed in iminium salts derived from... 

Exposure of the benzodioxepine 371 to catalytic amounts of Cu-(hexafluoroacetylacetonate)2 [Cu(hfacac)2] resulted in the formation of the 1,4-benzodioxocin 372, as main product (56%), and the 1,3-benzodioxocin 373, as minor product (19%). An endocyclic 1,2-shift to the ketal carbon resulted in the formation of 372, whereas 373 was the result of an exocyclic 1,2-shift to the benzylic position (Equation 46) <1997JOC3902>. 

---