Highly Regioselective Synthesis of Polysubstituted Tetrahydroquinolines by an Iodine-Induced Tandem Cyclization Reaction from Propargylic Alcohols and Amines

Progress in the Chemistry of Tetrahydroquinolines

Tetrahydroquinoline is one of the most important simple nitrogen heterocycles, being widespread in nature and present in a broad variety of pharmacologically active compounds. This Review summarizes the progress achieved in the chemistry of tetrahydroquinolines, with emphasis on their synthesis, during the period from mid-2010 to early 2018.

A simple Synthesis of the Debrominated Analogue of Veranamine

A facile synthesis of 4,5,5-trimethyl-5,6-dihydrobenzo[c][2,7]naphthyridine, the debrominated analogue of the marine alkaloid veranamine, has been achieved in three steps with a 38% overall yield. from the commercially available 2-bromoaniline. The key benzo[c][2,7]naphthyridine moiety was constructed using a Sonogashira coupling, a tandem Rupe rearrangement–Donnelly–Farrell cyclisation and a Diels–Alder reaction as the key steps. The synthetic strategy allows rapid access to various analogues of veranamine.

Acid-catalyzed domino reactions of tetraarylbut-2-yne-1,4-diols. Synthesis of conjugated indenes and inden-2-ones

The reaction of tetraarylbut-2-yne-1,4-diols with electron-rich aromatic compounds at room temperature, under p-TsOH catalysis, affords substituted polycyclic aromatic indene derivatives through a domino reaction involving the formation of a cationic allenylium intermediate. This species can undergo a series of competitive intramolecular cascade reactions, leading to a conjugated inden-2-one. This simple method allows the efficient synthesis of substituted indenes and inden-2-ones, in two steps, from aromatic ketones.