Efficient and Practical One‐Pot Conversions of N‐Tosyltetrahydroisoquinolines into Isoquinolines and of N‐Tosyltetrahydro‐β‐carbolines into β‐Carbolines through Tandem β‐Elimination and Aromatization

Abstract An efficient, practical, and general method for conversions of N ‐tosyltetrahydroisoquinolines ( N ‐tosyl‐THIQs) into isoquinolines and of N ‐tosyltetrahydro‐β‐carbolines ( N ‐tosyl‐THBCs) into β‐carbolines is described. Treatment of N ‐tosyl‐THIQs or N ‐tosyl‐THBCs with base in dimethyl sulfoxide afforded dihydroisoquinolines or dihydro‐β‐carbolines as intermediates, and these were then oxidized in situ by molecular oxygen to furnish isoquinolines or β‐carbolines in good to high yields. Both one‐pot conversions occurred through tandem β‐elimination and aromatization.