MECHANISM OF THE REARRANGEMENT OF 2(VINYLOXY)ALKYL TO 4-KETOBUTYL RADICALS

The rearrangement of 2-(vinyloxy)alkyl to 4-ketobutyl radicals has bee n demonstrated to proceed by a two step mechanism involving initial 5- endo-trigonal cyclization to give a tetrahydrofuranyl radical which th en fragments to the final radical. Fragmentation of the tetrahydrofura nyl radicals is demonstrated by their generation from the correspondin g 2-(ethylthio)-tetrahydrofurans with stannanes and AIBN. The rearrang ement reaction is completely blocked when the intermediate tetrahdrofu ranyl radical is set up to undergo a 5-hexenyl rearrangement.