Metallation-Addition Reactions of Enantiopure Aromatic Sulfoxides

Significance

This is an interesting approach to chiral α-arylamines, using a chiral tert-butyl sulf­oxide moiety as a removable ortho-directing group for a metallation reaction, and at the same time as a chiral auxiliary for the diastereoselective 1,2-addition of the formed aryllithium species. The starting chiral aryl sulfoxides are easily prepared from commercial tert-butyl tert-butanethiosulfinate and the corresponding aryllithium compounds. The sulfoxide group is readily cleaved from the products by treatment with Raney Ni in EtOH. Some heterocyclic systems were used in the reaction sequence with good results.