Chemo-, regio-, and stereoselectivity in acid-catalyzed hydromethoxylation of tricyclo[4.1.0.02,7]hept-1-yl and 7-methyltricyclo[4.1.0.02,7]hept-1-yl phenyl sulfones

Abstract

Hydromethoxylation of tricyclo[4.1.0.02,7]hept-1-yl and 7-methyltricyclo[4.1.0.02,7]hept-1-yl phenyl sulfones with methanol at 20°C in the presence of a catalytic amount of perchloric acid is initiated by the endo attack of proton at the C1 atom, and the subsequent cleavage of the side C1–C2 bond leads to formation of mixtures of diastereoisomeric exo-7-phenylsulfonyl-2-methoxybicyclo[4.1.0]heptanes, the endo-2 isomer prevailing. Probable factors responsible for the observed chemo-, regio-, and stereoselectivity of the addition are discussed.