Selectivity of Purine Alkylation by a Quinone Methide. Kinetic or Thermodynamic Control?

The alkylation reaction of 9-methyladenine and 9-methylguanine (as prototype substrates of deoxyadenosine and -guanosine), by the parent o-quinone methide (o-QM), has been investigated in the gas phase and in aqueous solution, using density functional theory at the B3LYP/6-311+G(d,p) level.