One-Pot Synthesis of 2- R-Naphtho[2,3- b]thiophene-4,9-diones via Cyclization of 2-(R-Ethynyl)-1,4-naphthoquinones with Na2S2O3

Denis S Baranov; Alexander A Popov; Danil A Nevostruev; Alexey A Dmitriev; Yurii V Gatilov; Elena S Kobeleva

doi:10.1021/acs.joc.1c00852

One-Pot Synthesis of 2- R-Naphtho[2,3- b]thiophene-4,9-diones via Cyclization of 2-(R-Ethynyl)-1,4-naphthoquinones with Na₂S₂O₃

J Org Chem. 2021 Sep 3;86(17):11361-11369. doi: 10.1021/acs.joc.1c00852. Epub 2021 Aug 4.

Authors

Denis S Baranov¹, Alexander A Popov¹, Danil A Nevostruev¹, Alexey A Dmitriev¹, Yurii V Gatilov², Elena S Kobeleva¹

Affiliations

¹ Voevodsky Institute of Chemical Kinetics and Combustion, Siberian Branch of the Russian Academy of Sciences, Novosibirsk 630090, Russian Federation.
² Vorozhtsov Novosibirsk Institute of Organic Chemistry, Siberian Branch of the Russian Academy of Sciences, Novosibirsk 630090, Russian Federation.

PMID: 34347465
DOI: 10.1021/acs.joc.1c00852

Abstract

The concise and efficient one-pot synthesis of 2-R-naphtho[2,3-b]thiophene-4,9-diones from 2-bromo-1,4-naphthoquinone and alkynes has been developed. The reaction proceeds through the formation of 2-(R-ethynyl)-1,4-naphthoquinones, which undergo transformation with Na₂S₂O₃ to 2-R-naphtho[2,3-b]thiophene-4,9-diones via C-H sulfuration, accompanied by the formation of the aromatic Bunte salt, followed by its air oxidation and 5-endo-dig cyclization. The protocol is characterized by simplicity, good tolerance for functional groups, relatively mild conditions, and commercially available starting compounds.