Gallou, Fabrice (2019) C,N-Disubstituted Biarylpalladacycles as Pre-catalysts for ppm Level Cross Couplings in Water Under Mild Conditions. ACS Catalysis, 9 (12). pp. 11647-11657.

Abstract

Various mono- and di-substitution patterns on the parent biarylamine skeleton characteristic of palladacycles, as well as the counterion effect, have been studied looking to increase the binding constant of the resulting palladacycle to the inner cores of nanomicelles in water, thereby reducing the amount of Pd needed for coupling reactions. Several substituted palladacycles containing readily accessible ligands were chosen for evaluation. The results indicate that: (1) pre-activation of
these pre-catalysts for Suzuki-Miyaura (SM) couplings can be avoided; (2) reactions could be performed with ca. half the loading of Pd as previously required for use of (Pd salts + ligand)
combinations; (3) the most effective palladacycle has been identified as that containing an isopropyl
group on both an aryl ring and on nitrogen, together with ligand EvanPhos and triflate as the counterion (P12). This pre-catalyst is also effective in other C-C bond forming reactions, such as Heck and Sonogashira couplings. No organic solvents were needed for these processes, while the aqueous reaction medium could be recycled several times. A 1–pot, 4–step sequence involving Suzuki-Miyaura, reduction, alkylation, and acylation reactions highlights the potential for this pre-catalyst to maximize synthetic gain while minimizing costs and waste generation.

Item Type:	Article
Date Deposited:	31 Dec 2019 00:45
Last Modified:	31 Dec 2019 00:45
URI:	https://oak.novartis.com/id/eprint/40651