Visible‐Light Photoredox‐Catalyzed Semipinacol‐Type Rearrangement: Trifluoromethylation/Ring Expansion by a Radical–Polar Mechanism. Issue 39 (1st June 2015)

• Record Type: Journal Article
• Authors: Sahoo, Basudev; Li, Jun‐Long; Glorius, Frank
• Is Part Of: Angewandte Chemie international edition. Volume 54:Issue 39(2015)
• Page Start: 11577
• Page End: 11580
• Publication Date: 2015-06-01
• Subjects: fluorine -- photocatalysis -- radical reactions -- ring expansion; Chemistry -- Periodicals; 540
• DOI: 10.1002/anie.201503210
• Languages: English
• ISSNs: 1433-7851

Abstract

Abstract: A visible‐light‐mediated photoredox‐catalyzed semipinacol‐type rearrangement proceeding via 1, 2 alkyl migration was developed. In this transformation, trifluoromethylation of the CC bond of α‐(1‐hydroxycycloalkyl)‐substituted styrene derivatives is followed by ring expansion of the 1‐hydroxycycloalkyl group to deliver novel cycloalkanones with all‐carbon quaternary centers. The reaction proceeds via a radical–polar mechanism, with trifluoromethylation (radical) and ring expansion (ionic) occurring in the same transformation. Abstract : Circle of light: A visible‐light‐mediated photoredox semipinacol‐type rearrangement proceeding by 1, 2 alkyl migration was developed. The transformation involves a radical–polar mechanism, in which photoinduced trifluoromethylation of a CC bond is followed by ring expansion of a cationic intermediate. This process constitutes the first report of ionic alkyl migration in photoredox catalysis and proceeds under mild conditions with visible light.