Palladium promoted coupling reactions are well studied and have found numerous applications. However, most of these experimental protocols suffer from various process limitations such as high reaction temperature requirements, limited substrate scope, and employment of expensive ligands often accompanied by only moderate yields. Difficulties in overcoming such challenges have impeded wider application of these protocols.
Prof. Anant R. Kapdi from the Matunga Institute of Chemical Technology, Mumbai, India, has developed a new water-soluble phosphatriazene ligand – PTABS (15-5715), which in combination with Pd(OAc)2 (46-1780, 46-1781), forms a powerful catalyst for a wide range of cross-coupling reactions for all four halonucleosides [1]. PTABS is a water soluble (506 mg/mL) zwitterionic ligand derived from the caged adamantane phosphine 15-5710 (Fig. 1), which upon coordination to Pd metal makes the resultant complex soluble in the aqueous phase [2].
Fig. 1. PTABS — water-soluble phosphatriazene ligand
Indeed, Pd/PTABS is able to catalyze column-free Suzuki-Miyaura, Sonogashira and Heck coupling of halonucleosides in neat water with high yields [1]. In addition, PTABS was effectively applied in Pd catalyzed low temperature amination [3] and etherification [4-6] reactions in organic solvents (DMF). Moreover, the Pd/PTABS system goes beyond the scope of the palladium-catalyzed coupling systems and is able to promote aminocarbonylation involving CO gas at relatively low temperatures [7].
References:
Featured Products
15-5710 1,3,5-Triaza-7-phosphaadamantane, min. 97% PTA (53597-69-6)
15-5715 4-((1R,3R,5S,7R)-1,3,5-Triaza-7-phosphaadamantan-1-ium-1-yl)butane-1-sulfonate, min. 98%, PTABS (1430837-91-4)
46-1780 Palladium(II) acetate, min. 98% (99.9+%-Pd) (3375-31-3)
46-1781 Palladium(II) acetate, 99+% (99.95+%-Pd) (3375-31-3)
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