Metal-Free Tandem Rearrangement/Lactonization: Access to 3,3-Disubstituted Benzofuran-2-(3H)-ones

Micol Santi; Darren M C Ould; Jan Wenz; Yashar Soltani; Rebecca L Melen; Thomas Wirth

doi:10.1002/anie.201902985

Metal-Free Tandem Rearrangement/Lactonization: Access to 3,3-Disubstituted Benzofuran-2-(3H)-ones

Angew Chem Int Ed Engl. 2019 Jun 3;58(23):7861-7865. doi: 10.1002/anie.201902985. Epub 2019 Apr 10.

Authors

Micol Santi¹, Darren M C Ould¹, Jan Wenz¹, Yashar Soltani¹, Rebecca L Melen¹, Thomas Wirth¹

Affiliation

¹ School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff, CF10 3AT, Wales, UK.

PMID: 30897253
DOI: 10.1002/anie.201902985

Abstract

A novel metal-free synthesis of 3,3-disubstituted benzofuran-2-(3H)-ones through reacting α-aryl-α-diazoacetates with triarylboranes is presented. Initially, triarylboranes were successfully investigated in α-arylations of α-diazoacetates, however in the presence of a heteroatom in the ortho position, the boron enolate intermediate undergoes an intramolecular rearrangement to form a quaternary center. The intermediate cyclizes to afford valuable 3,3-disubstituted benzofuranones in good yields.

Keywords: benzofuranone; boron; diazo compounds; metal-free conditions; rearrangement.