Polar,Aprotic Solvents Solvents should be able to "cage"the metal cation CH3SCH:CHCN HCN(CH3)CHCCH DMSO acetonitrile DMF acetone Polar,protic solvents lower energy of nucleophile HOCH3 by solvation CH3OH---Br---HOCH; CH3OH Polar, Aprotic Solvents by solvation Polar, protic solvents lower energy of nucleophile C H3O H HOCH3 C H3O H Br HOCH3 acetone O C H3 C N C H3 CCH3 DMSO acetonitrile DMF O HCN(CH3 ) 2 O C H3 SCH3 Solvents should be able to "cage" the metal cation