Buchwald–Hartwig cross-coupling of amides (transamidation) by selective N–C(O) cleavage mediated by air- and moisture-stable [Pd(NHC)(allyl)Cl] precatalysts: catalyst evaluation and mechanism. Issue 3 (9th January 2020)

• Record Type: Journal Article
• Authors: Li, Guangchen; Zhou, Tongliang; Poater, Albert; Cavallo, Luigi; Nolan, Steven P.; Szostak, Michal
• Is Part Of: Catalysis science & technology. Volume 10:Issue 3(2020)
• Page Start: 710
• Page End: 716
• Publication Date: 2020-01-09
• Subjects: Catalysis -- Periodicals; 541.395
• DOI: 10.1039/c9cy02080b
• Languages: English
• ISSNs: 2044-4753

Abstract

Abstract : We report a combined experimental and computational study of the Buchwald–Hartwig cross-coupling of amides by N–C(O) cleavage (transamidation) using well-defined, air- and moisture-stable [Pd(NHC)(allyl)Cl] precatalysts. Abstract : The Pd–NHC-catalyzed acyl-type Buchwald–Hartwig cross-coupling of amides by N–C(O) cleavage (transamidation) provides a valuable alternative to the classical methods for amide synthesis. Herein, we report a combined experimental and computational study of the Buchwald–Hartwig cross-coupling of amides using well-defined, air- and moisture-stable [Pd(NHC)(allyl)Cl] precatalysts. Most crucially, we present a comprehensive evaluation of a series of distinct Pd(ii )–NHC precatalysts featuring different NHC scaffolds and throw-away ligands for the synthesis of functionalized amides that are not compatible with stoichiometric transition-metal-free transamidation methods. Furthermore, we present evaluation of the catalytic cycle by DFT methods for a series of different Pd(ii )–NHC precatalysts. The viability of accessing NHC-supported acyl-palladium(ii ) amido complexes will have implications for the design and development of cross-coupling methods involving stable amide electrophiles.