Regiochemical control of the ring-opening of aziridines by means of chelating processes. Part 4: Regioselectivity of the opening reactions with MeOH of 1-(benzyloxy)-2,3- and -3,4-N-(methoxycarbonyl)aziridoalkanes under condensed and gas-phase operating conditions

The regioselectivity of the addition reaction of MeOH both in the condensed phase (MeOH/H₂SO₄) and in the gas-phase (MeOH/D₃⁺) was examined in a series of activated aziridines. The results indicate that gas-phase operating conditions are particularly favorable for the occurrence of D⁺-mediated chelated bidentate species, which influence the regioselectivity of the opening process. In the condensed phase, the chelating MeOH/LiClO₄ protocol turned out to be decidedly less effective for regioselectivity and also in determining the composition of the reaction mixture.