Borocyclopropanation of Styrenes Mediated by UV‐light Under Continuous Flow Conditions. (12th September 2018)

• Record Type: Journal Article
• Authors: Sayes, Morgane; Benoit, Guillaume; Charette, André B.
• Is Part Of: Angewandte Chemie. Volume 130:Number 41(2018)
• Page Start: 13702
• Page End: 13706
• Publication Date: 2018-09-12
• Subjects: Borcyclopropane -- Durchflussverfahren -- Photochemie -- Radikale -- UV-Licht; Chemistry -- Periodicals; 540
• DOI: 10.1002/ange.201807347
• Languages: English
• ISSNs: 0044-8249

Abstract

Abstract: Herein, we report a user‐friendly and metal‐free UV‐A light mediated borocyclopropanation of styrenes using continuous flow technology. A broad range of styrene derivatives can be cyclopropanated in good yields within 1 h residence time to produce highly valuable cyclopropylboronate esters with modest to good diastereoselectivities. The reaction is also applicable to α‐substituted styrenes. Mechanistic studies support a photoredox process during which xanthone, a well‐known organic photosensitizer, can easily reach a photoexcited state that is available for both an oxidative and a reductive quenching.