Lewis Acid Promoted Homodimerization of Styrene Diols: An Efficient Approach toward 2-Phenylnaphthalenes

Abstract

We report a straightforward, metal-free, efficient protocol for the synthesis of 2-phenylnaphthalenes from 1-phenylethane-1,2-diols under mild conditions. In this strategy, 1,1,1,3,3,3-hexafluoro-2-propanol is used as a solvent that stabilizes the reaction intermediate. An in situ IR experiment revealed that the reaction proceeds through the formation of phenylacetaldehyde followed by a [4+2] Diels–Alder reaction. Several control experiments were performed to gain mechanistic insights into the reaction.

Synthesis of Azepinoindoles and Oxepinoindoles through Brønsted-Acid-Catalyzed Cyclization of an In Situ Generated Dihydrospiroquinoline Intermediate

“…Several reports of the nucleophilic attack at the carbonyl moiety of QMAs have been documented for the synthesis of natural products or other functional compounds . On the basis of our longstanding interest in intramolecular ring cyclization, we envisioned utilizing this reactive intermediate as an electrophilic aryl group source and tryptamine/tryptaphol as a nucleophilic partner to construct aza- or oxa-heterocycles. Herein, we disclose a mild and metal-free, one-pot synthetic approach to produce THB-[2,3]-azepino­[4,5- b ]­indoles and DHB-[2,3]­oxepino­[4,5- b ]­indoles through intramolecular ring cyclization.…”