Me3(OMe)tBuXPhos: A Surrogate Ligand for Me4tBuXPhos in Palladium-Catalyzed C–N and C–O Bond-Forming Reactions
摘要:
A new biarylphosphine ligand, Me-3(OMe)tBuXPhos (L3), was designed as a surrogate for Me(4)tBuXPhos (L1). The Me-3(OMe)tBuXPhos could be prepared in a chromatography-free manner from inexpensive and readily available 2,3,6-trimethylphenol. Comparative studies demonstrated that a catalyst based on Me-3(OMe)tBuXPhos displayed the same reactivity as a catalyst based on Me(4)tBuXPhos for Pd-catalyzed C-N and C-O bond-forming processes.
Mild and Highly Selective Palladium-Catalyzed Monoarylation of Ammonia Enabled by the Use of Bulky Biarylphosphine Ligands and Palladacycle Precatalysts
作者:Chi Wai Cheung、David S. Surry、Stephen L. Buchwald
DOI:10.1021/ol401612c
日期:2013.7.19
A method for the Pd-catalyzed arylation of ammonia with a wide range of aryl and heteroaryl halides, including challenging five-membered heterocyclic substrates, is described. Excellent selectivity for monoarylation of ammonia to primary arylamines was achieved under mild conditions or at rt by the use of bulky biarylphosphine ligands (L6, L7, and L4) as well as their corresponding aminobiphenyl palladacycle