Switchable solvent-controlled divergent synthesis: an efficient and regioselective approach to pyrimidine and dibenzo[ b , f ][1,4]oxazepine derivatives

Herein an efficient and regioselective method for the divergent synthesis of pyrimidine and dibenzo[ b , f ][1,4]oxazepine (DBO) derivatives from the same starting materials was developed. The selectivity can be rationally tuned via the judicious choice of reaction solvents. With 1,4-dioxane used as the solvent, 2-pyrimidinyloxy- N -arylbenzylamines ( O -substituted pyrimidines) were obtained in excellent yields, whereas use of dimethyl sulfoxide (DMSO) as solvent afforded N -(2-hydroxybenzyl)- N -phenylpyrimidin-2-amines ( N -substituted pyrimidines) in excellent yields, or DBO derivatives in moderate to excellent yields. The easily-accessible substrates and operational simplicity make the process suitable for further exploration. The reaction mechanism involved the S N Ar reaction and Smiles rearrangement as key steps.