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

The conversion of alpha-benzocycloalkenones to homologous beta-benzocyclo-alkenones 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)3.3H2O or the Prevost combination (AgNO3/I2) are employed in the oxidation step.