Copper and Rhodium Relay Catalysis for Selective Access to cis-2,3-Dihydroazepines

Org Lett. 2021 Aug 20;23(16):6450-6454. doi: 10.1021/acs.orglett.1c02262. Epub 2021 Aug 5.

Abstract

A new catalytic protocol to access synthetically challenging cis-2,3-dihydroazepines is reported. The reaction starts with readily available dienals, alkynes, and sulfonyl azides as the substrates and employs copper and rhodium as relay catalysts. Key steps include a copper-catalyzed reaction between an alkyne and a sulfonyl azide to form a triazole intermediate. The subsequent activation of this triazole intermediate by a rhodium catalyst, followed by a reaction with the dienal substrate, eventually leads to the dihydroazepine product. The regio- and stereochemistries of the products are believed to be controlled through a stereospecific conrotatory 8π-electrocyclization process against a possible competing 6π-electrocyclization process.

Publication types

  • Research Support, Non-U.S. Gov't