Direct addition of tetrahydroisoquinoline derived amides to arylalkenes has been achieved in the presence of KOt-Bu/DMF. Both intermolecular and intramolecular reactions could occur in good yields. α-Amido alkyl radicals are proposed to be generated under the reaction conditions. The reaction is efficient for the synthesis of seven-membered nitrogen heterocycles. A homoprotoberberine was prepared conveniently via this method.