title: Visible light photoredox-catalyzed deoxygenation of alcohols.
abstract: Carbon-oxygen single bonds are ubiquitous in natural products whereas efficient methods for their reductive defunctionalization are rare. In this work an environmentally benign protocol for the activation of carbon-oxygen single bonds of alcohols towards a reductive bond cleavage under visible light photocatalysis was developed. Alcohols were activated as 3,5-bis(trifluoromethyl)-substituted benzoates and irradiation with blue light in the presence of [Ir(ppy)2(dtb-bpy)](PF6) as visible light photocatalyst and Hünig's base as sacrificial electron donor in an acetonitrile/water mixture generally gave good to excellent yields of the desired defunctionalized compounds. Functional group tolerance is high but the protocol developed is limited to benzylic, α-carbonyl, and α-cyanoalcohols; with other alcohols a slow partial C-F bond reduction in the 3,5-bis(trifluoromethyl)benzoate moiety occurs.
authors.affiliation: Institute of Organic Chemistry, University of Regensburg, 93053 Regensburg, Germany.
authors.forename: Daniel
authors.initials: D
authors.lastname: Rackl
authors.affiliation: Institute of Organic Chemistry, University of Regensburg, 93053 Regensburg, Germany.
authors.forename: Viktor
authors.initials: V
authors.lastname: Kais
authors.affiliation: Institute of Organic Chemistry, University of Regensburg, 93053 Regensburg, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Kreitmeier
authors.affiliation: Institute of Organic Chemistry, University of Regensburg, 93053 Regensburg, Germany.
authors.forename: Oliver
authors.initials: O
authors.lastname: Reiser
keywords: C–O bond activation; deoxygenation; photochemistry; photoredox catalysis; visible light