Metal‐Free Tandem Rearrangement/Lactonization: Access to 3, 3‐Disubstituted Benzofuran‐2‐(3H)‐ones. Issue 23 (10th April 2019)

• Record Type: Journal Article
• Authors: Santi, Micol; Ould, Darren M. C.; Wenz, Jan; Soltani, Yashar; Melen, Rebecca L.; Wirth, Thomas
• Is Part Of: Angewandte Chemie international edition. Volume 58:Issue 23(2019)
• Page Start: 7861
• Page End: 7865
• Publication Date: 2019-04-10
• Subjects: benzofuranone -- boron -- diazo compounds -- metal-free conditions -- rearrangement; Chemistry -- Periodicals; 540
• DOI: 10.1002/anie.201902985
• Languages: English
• ISSNs: 1433-7851

Abstract

Abstract: A novel metal‐free synthesis of 3, 3‐disubstituted benzofuran‐2‐(3 H )‐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. Abstract : Every step you take : 3, 3‐Disubstituted lactones were obtained in excellent yields through the reaction of diazo compounds with triarylboranes. The multistep reaction proceeds through an aryl transfer followed by migration of the benzyl group and finally a cyclization reaction.