No 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.

No abstract

A clean and general DBU‐catalyzed epimerization at C‐12a position of the tadalafil‐like tetracyclic compounds has been fully studied. In addition, by using this clean epimerization as the key step, four stereomers of 6‐d1‐tadalafil were stereodivergently synthesized from both L‐ and D‐tryptophan methyl ester hydrochlorides and deuterated piperonal.

No abstract