Reactions of 2‐chloro‐2‐(4‐pyridyl)propane with nucleophiles. Substitution on tertiary carbon

The reaction of 2‐chloro‐2‐(4‐pyridyl)propane ( 2 ) with lithium 2‐propanenitronate affords the C ‐alkylation product 2‐nitro‐3‐(4‐pyridyl)‐2,3‐dimethylbutane ( 3 ), the Michael‐adduct 2‐nitro‐2‐methyl‐4‐(4‐pyridyl)pentane ( 4 ), 4‐isopropenylpyridine ( 5 ) and 2‐(4‐pyridyl)‐2‐propanol ( 6 ). Of these four products, only the formation of 3 is suppressed when the reaction is performed in the presence of radical inhibitors. The reaction of compound 2 with sodium azide gives the tertiary substitution product 2‐azido‐2‐(4‐pyridyl)propane ( 8 ). The reaction is not influenced by radical inhibitors. This is also the case in the reaction of 2 with sodium benzenethiolate, which affords 2‐mercaptophenyl‐2‐(4‐pyridyl)propane ( 9 ) and 1‐mercaptophenyl‐2‐(4‐pyridyl)propane ( 10 ). Compound 5 , the product of an E 2 ‐type elimination is also formed in the azide and thiolate reactions. A Michael type addition of sodium benzenethiolate to 5 explains the formation of 10 . Similarly, generation of 5 in reactions of 2 with sodium methanethiolate and sodium cyanide accounts for the formation of 1‐mercaptomethyl‐2‐(4‐pyridyl)propane ( 11 ) and 3‐(4‐pridyl)butanenitrile ( 12 ), respectively.