Synergistic Gold and Iron Dual Catalysis: Preferred Radical Addition toward Vinyl–Gold Intermediate over Alkene

Abstract

A dual catalytic approach enlisting gold and iron synergy is described. This method offers readily access to substituted heterocycle aldehydes via oxygen radical addition to vinyl-gold intermediates under Fe catalyst assistance. This system shows good functional group compatibility for the generation of substituted oxazole, indole, and benzofuran aldehydes. Mechanistic evidence greatly supports selective radical addition to an activated vinyl-Au double bond over alkene. This unique discovery offers a new avenue with great potential to further extend the synthetic power and versatility of gold catalysis.

Gold‐Catalyzed Cross‐Coupling Reactions: An Overview of Design Strategies, Mechanistic Studies, and Applications

“…[53][54][55][56] Compared with the advances in heterogeneous goldc atalysis, the field of homogeneous gold catalysis startedt og row only in the first decade of the 21st century.O ver the past two decades, homogeneousg old catalysis has emerged as an eminent synthetic methodology.T he progress in the syntheses and applications of Au catalysts, related reaction mechanisms, and the future prospects of traditional Au I -catalyzed reactions have been reviewed by the groups of Hashmi, [57][58][59][60][61][62] Fürstner, [63,64] To ste, [65] Echavarren, [66][67][68] and others. [92,93,102,[94][95][96][97][98][99][100][101] Some reactions are best catalyzed when multiple Au centers are available to activate the reactants and/or intermediates. Being ah eavy atom with a5 d 10 6s 1 electronic configuration, the relativistic effects strongly affect the dynamics of the valence electrons of Au.…”

ortho‐Oxygenative 1,2‐Difunctionalization of Diarylalkynes under Merged Gold/Organophotoredox Relay Catalysis

“…In light of the well-established reactivity of Eosin Yasao rganophotocatalyst, [16] especially in combination with molecular oxygen;w ed ecided to use Eosin Yi n combination with gold catalysts. (entries [8][9][10][11][12]. The structureo ft he compound 3a was confirmedb yX -ray crystallography.…”

“…[11] As far as binary catalysis is concerned, Jiao and Shi employed aA u/Fe catalyst system for the synthesis of heterocyclic aldehydes using molecular oxygen as an oxygenating agent (Scheme 1a). [12] Mechanistically,a ni ntriguingp athway involving aF e-assisted oxygen radical addition to in situ generated vinyl-gold intermediates was found to be operating. In addition to molecular oxygen,o xygenation reactions utilizing photochemically generated singlet oxygen ( 1 O 2 )h as also evolveda sa na lternative method.…”

Synthesis of 2,2,2‐Trifluoroethyl Oxazoles, Oxazolines and Furans via Alkyne Oxytrifluoromethylation

“…Benzylic trifluoromethylation is an alternative method to prepare ArCH 2 CF 3 , relying on the cross‐coupling of benzylic halides or boronic acids or C−H bond with various CF 3 reagents (Scheme b) . Despite these two major types of aromatic post‐functionalization methods, it is highly desirable to prepare ArCH 2 CF 3 compounds involving de novo construction of the aromatic ring and concurrent CH 2 CF 3 incorporation …”