Copper‐Catalyzed Coupling of Triaryl‐ and Trialkylindium Reagents with Aryl Iodides and Bromides through Consecutive Transmetalations

Abstract

An efficient copper(I)-catalyzed coupling of triaryl and trialkylindium reagents with aryl iodides and bromides is reported. The reaction proceeds at low catalyst loadings (2 mol%) and generally only requires 0.33 equivalents of the triorganoindium reagent with respect to the aryl halide as all three organic nucleophilic moieties of the reagent are transferred to the products through consecutive transmetalations. The reaction tolerates a variety of functional groups and sterically hindered substrates. Furthermore, preliminary mechanistic studies that entailed the synthesis and characterization of potential reaction intermediates offered a glimpse of the elementary steps that constitute the catalytic cycle.

Silver‐Catalyzed Arylation of (Hetero)arenes via Oxidative Benzylic C−C Bond Cleavage of Benzyl Alcohols/ Benzaldehyde

“…However, when we used mix‐metallic catalysts for the present study; we could not obtain desired arylated products . However, Ag(I) carbocatalyst gave a positive result with ∼16% arylation yield, which prompted us for further catalyst manipulations to furnish better results.…”

“…Constructing upon the work of Minisci and co‐workers, we decided to employ Ag (I) for in‐situ oxidation of benzyl alcohol to form benzoic acid followed by decarboxylative coupling reactions . In this context, a series of Ag(I) salts, metallic alloys loaded over carbocatalyst‘s as well as metal‐organic frameworks were employed as catalysts for the arylation purpose …”

Copper-Catalyzed Cross-Couplings of Organometallic Reagents with and without Assistance from PN Ligands

“…22 Under our reaction conditions, these copper complexes are catalytically active and have been shown to be potential reaction intermediates in cross-couplings of organometallic reagents such as organosilicon, 23 organoboron, 19 and organoindium. 20 Formation of such stable complexes has also enabled us to conduct cross-coupling reactions at low catalyst loadings (2 mol%). [19][20] Our results for cross-couplings of different organometallic reagents with aryl halides involving these P,N-ligands and the underlying reaction mechanisms are described in the following sections.…”

“…20 Formation of such stable complexes has also enabled us to conduct cross-coupling reactions at low catalyst loadings (2 mol%). [19][20] Our results for cross-couplings of different organometallic reagents with aryl halides involving these P,N-ligands and the underlying reaction mechanisms are described in the following sections. …”

“…In this regard, we recently demonstrated that [CuOMe], in combination with a P,N-ligand, was an effective catalytic system, enabling us to cross-couple a variety of triorganoindium reagents with aryl halides (Scheme 5). 20 The reaction typically requires only one-third equivalents of triorganoindium reagents and proceeds through three consecutive transmetalations when NaOMe is utilized as a source of MeO -anion in combination with PN-2 and copper(I) iodide. The MeO -anion is required to generate R 2 InOMe and RIn(OMe) 2 from R 3 In as reactive intermediates for the second and third transmetalations.…”