Quantum-chemical investigation of isocyanate reactions with linear methanol associates: V. Aryl isocyanate reactions with linear methanol associates

The mechanism of addition of linear methanol associates (monomer, dimer, trimer) to aryl isocyanates at their C=N and C=O bonds was investigated applying the quantum-chemical method B3LYP/6-311++G(df,p). Notwithstanding the electronic character of substituents in the aromatic ring of the isocyanates all reactions proceed through concerted asymmetric late transition states. The addition to the C=N bond is considerably more preferable than to the C=O bond. In the transformations under consideration the intermolecular donor-acceptor interactions between the reagents result in the appearance of abnormal selectivity.