Catalysis

Pd(II)-Catalyzed C(alkenyl)–H Activation Facilitated by a Transient Directing Group

Authors

Abstract

Palladium(II)-catalyzed C(alkenyl)–H alkenylation enabled by a transient directing group (TDG) strategy is described. The dual catalytic process takes advantage of reversible condensation between an alkenyl aldehyde substrate and an amino acid TDG to facilitate coordination of the metal catalyst and subsequent C(alkenyl)–H activation by a tailored carboxylate base. The resulting palladacycle then engages an acceptor alkene, furnishing a 1,3-diene with high regio- and E/Z-selectivity. The reaction enables the synthesis of enantioenriched atropoisomeric 2-aryl-substituted 1,3-dienes, which have seldom been examined in previous literature. Catalytically relevant alkenyl palladacycles were synthesized and characterized by X-ray crystallography, and the energy profiles of the C(alkenyl)–H activation step and the stereoinduction model were elucidated by density functional theory (DFT) calculations.

Content

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Supplementary material

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Supporting Information
experimental procedures, copies of NMR spectra, crystallographic information, and computational details
Thumbnail image of 4.cif
4.cif
Compound 4 - Crystallographic Information File
Thumbnail image of 29.cif
29.cif
Compound 29 - Crystallographic Information File