Synthesis of N-[(1,1-dimethyl-2-hydroxy)ethyl]-N′-phenylthiourea (2a): To a stirred solution of 2-amino-2-methyl-1- propanol 1a (0.44 mL, 4.59 mmol, 110 M%) in THF (10 mL) under nitrogen at room temperature was added a solution of phenyl isothiocyanate (0.50 mL, 4.18 mmol, 100