Chemoselective Reactions of 4,6-Dichloro-2-(methylsulfonyl)pyrimidine and Related Electrophiles with Amines

Chemoselective S NAr reactions of 4,6-dichloro-2-(methylsulfonyl)pyrimidine and several related electrophiles with amines and their derivatives are described. In the presence of weak bases anilines and secondary aliphatic amines selectively displace the chloride group. Deprotonated anilines and their carbonyl derivatives displace the sulfone group. Sterically and electronically unbiased primary aliphatic amines selectively displace the sulfone group in 4,6-dichloro-2-(methylsulfonyl)pyrimidine; however, their reactions with other electrophiles generally are less selective. Steric-driven selectivity explanation was proposed.