Sequential ene reactions-II : Synthesis of bicyclic adducts with angular methyl groups. in situ oppenauer oxidation'

Abstract

The sequential ene reaction annelation sequence has been shown to be applicable to 2- and 3- substituted methylenecycloalkanes. Methyl groups in the 2-position are transformed into angular methyl groups in decalin or indane derivatives. The chloromethylaluminum alkoxides produced in these reactions, i.e. 3 and 7, undergo an Oppenauer oxidation in situ in the presence of excess acrolein to give the corresponding ketone in good yield. Using these procedures, indenone 8a has been prepared from 4a in one pot in 60% yield.