Application of [hydroxy(tosyloxy)iodo]benzene in the Wittig-Ring expansion sequence for the synthesis of beta-benzocycloalkenones from alpha-benzocycloalkenones

The conversion of alpha-benzocycloalkenones to homologous beta-benzocycloalkenones containing six, seven and eight-membered rings is reported. This was accomplished via a Wittig olefination-oxidative rearrangement sequence using [hydroxy(tosyloxy)iodo] -benzene (HTIB) is the oxidant, that enables the synthesis of regioisomeric pairs of methyl-substituted beta-benzocycloalkenones. The incorporation of carbon-13 at C-1 of the beta-tetralone nucleus was also demonstrated. The Wittig-HTIB approach is a useful alternative to analogous sequences in which Tl(NO3)(3)center dot 3H(2)O or the Prevost combination (AgNO3/I-2) are employed in the oxidation step.