Treatment of both primary alcohols 1a, b and secondary amines 1c, d, tethered to a Michael acceptor with (R)-phenylethyl isocyanate in the presence of DBU gave in good yield and high stereoselection diastereomeric mixtures of oxazolidin-2-ones 2a, b and 3a, b and imidazolidin-2-ones 2c, d and 3c, d, respectively. The cyclisation reaction was studied computationally by ab initio quantum mechanical methods. The observed stereoselectivity ...
