Development of highly electron-deficient and less sterically-hindered phosphine ligands possessing 1,3,5-triazinyl groups

Highly electron-deficient and less sterically-hindered phosphine ligands with two or three 1,3,5-triazinyl groups on the phosphorus atoms have been synthesized and examined in transition metal-catalyzed reactions for the first time. Due to the lack of any hydrogens or substituents at ortho-positions of the 1,3,5-triazine towards the phosphorous atom, it is considered that the steric hindrance of the tris(triazinyl)phosphine ligand to a metal center is least among triarylphosphine ligands. In the Stille coupling of aryl iodides, these electron-poor phosphine ligands provided good product yields compared to hitherto well-known phosphine ligands. (C) 2017 Elsevier B.V. All rights reserved.