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Visible-Light Photocatalytic Decarboxylation of ?,?-Unsaturated Carboxylic Acids: Facile Access to Stereoselective Difluoromethylated Styrenes in Batch and Flow.

ABSTRACT: The development of synthetic methodologies which provide access to both stereoisomers of ?,?-disubstituted olefins is a challenging undertaking. Herein, we describe the development of an operationally simple and stereoselective synthesis of difluoromethylated styrenes via a visible-light photocatalytic decarboxylation strategy using fac-Ir(ppy)3 as the photocatalyst. Meta- and para-substituted cinnamic acids provide the expected E-isomer. In contrast, ortho-substituted cinnamic acids yield selectively the less stable Z-product, whereas the E-isomer can be obtained via continuous-flow processing through accurate control of the reaction time. Furthermore, our protocol is amenable to the decarboxylative difluoromethylation of aryl propiolic acids.

SUBMITTER: Wei XJ

PROVIDER: S-EPMC5666695 | biostudies-literature | 2017 Oct

REPOSITORIES: biostudies-literature

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Visible-Light Photocatalytic Decarboxylation of α,β-Unsaturated Carboxylic Acids: Facile Access to Stereoselective Difluoromethylated Styrenes in Batch and Flow.

Wei Xiao-Jing XJ Boon Wout W Hessel Volker V Noël Timothy T

ACS catalysis 20170911 10

The development of synthetic methodologies which provide access to both stereoisomers of α,β-disubstituted olefins is a challenging undertaking. Herein, we describe the development of an operationally simple and stereoselective synthesis of difluoromethylated styrenes via a visible-light photocatalytic decarboxylation strategy using fac-Ir(ppy)3 as the photocatalyst. Meta- and para-substituted cinnamic acids provide the expected E-isomer. In contrast, ortho-substi ...[more]

PMID: 29109904

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