Aromatic substituent effect on the stereoselectivity of the gas-phase acid-induced ring opening in 9,10-oxides derived from trans-1,2,3,4,4a,10a-hexahydrophenanthrene
The effect of the aromatic ringsubstituents on the product distribution of the gas-phase acid-induced ring opening of benzocondensed epoxides 2a and 2b with MeOH was examined and compared with results from methanolysis. The observed syn/anti diastereoselectivity is strictly dependent on the type of the aromatic ringsubstituent (6-OCH3 or 7-Br), and a very satisfactory Hammett-type linear correlation