Mechanism of the Rearrangement of 2-(Vinyloxy)alkyl to 4-Ketobutyl Radicals

Article abstract of DOI:10.1016/S0040-4020(01)89539-9

The rearrangement of 2-(vinyloxy)alkyl to 4-ketobutyl radicals has been demonstrated to proceed by a two step mechanism involving initial 5-endo-trigonal cyclization to give a tetrahydrofuranyl radical which then fragments to the final radical.Fragmentation of the tetrahydrofuranyl radicals is demonstrated by their generation from the corresponding 2-(ethylthio)-tetrahydrofurans with stannanes and AIBN.The rearrangement reaction is completely blocked when the intermediate tetrahydrofuranyl radical is set up to undergo a 5-hexenyl rearrangement.