Imidazolin‐2‐ylidenaminophosphines as Highly Electron‐Rich Ligands for Transition‐Metal Catalysts. Issue 40 (10th August 2015)

• Record Type: Journal Article
• Authors: Wünsche, Marius A.; Mehlmann, Paul; Witteler, Tim; Buß, Florenz; Rathmann, Patrick; Dielmann, Fabian
• Is Part Of: Angewandte Chemie international edition. Volume 54:Issue 40(2015)
• Page Start: 11857
• Page End: 11860
• Publication Date: 2015-08-10
• Subjects: cross‐coupling -- ligand design -- ligand effects -- palladium -- phosphine ligands; Chemistry -- Periodicals; 540
• DOI: 10.1002/anie.201504993
• Languages: English
• ISSNs: 1433-7851

Abstract

Abstract: A variety of chemical transformations benefit from the use of strong electron‐donating ancillary ligands, such as alkylphosphines or N‐heterocyclic carbenes when electron‐rich metal centers are required. Herein, we describe a facile and highly modular access to monodentate and bidentate imidazolin‐2‐ylidenamino‐substituted phosphines. Evaluation of the phosphine's electronic properties substantiate that the formal replacement of alkyl or aryl groups by imidazolin‐2‐ylidenamino groups dramatically enhance their donor ability beyond that of alkylphosphines and even N‐heterocyclic carbenes. The new phosphines have been coordinated onto palladium(II) centers, and the beneficial effect of the novel substitution patterns has been explored by using the corresponding complexes in the palladium‐catalyzed Suzuki–Miyaura cross‐coupling reaction of non‐activated aryl chloride substrates. Abstract : Upgrading phosphines : A conceptually new approach to a family of extremely electron‐rich phosphines is based on the use of imidazolin‐2‐ylidenamino groups directly attached to the phosphorus atom. The steric and electronic properties of the new ligands can be easily varied owing to the general and modular synthesis, which provides new prospects for phosphine ligands in catalysis.