Carboxylate-assisted ruthenium(II)-catalyzed C–H arylations of 5-aryl tetrazoles: step-economical access to Valsartan
摘要:
Carboxylate assistance was key to success for highly efficient ruthenium-catalyzed direct ortho-arylations of tetrazolyl-substituted arenes with aryl halides and triflates in the absence of phosphine ligands. Thus, ruthenium(II) biscarboxylates allowed for C-H bond functionalizations with excellent chemo- and site-selectivities, which set the stage for an atom- and step-economical access to key angiotensin-II-receptor blockers. Mechanistic studies revealed the C-H bond metalation to be reversible, and were suggestive of a rate-determining reductive elimination. (C) 2013 Elsevier Ltd. All rights reserved.
Single-Component Phosphinous Acid Ruthenium(II) Catalysts for Versatile C−H Activation by Metal-Ligand Cooperation
作者:Daniel Zell、Svenja Warratz、Dmitri Gelman、Simon J. Garden、Lutz Ackermann
DOI:10.1002/chem.201504851
日期:2016.1.22
Well‐defined ruthenium(II) phosphinousacid (PA) complexes enabled chemo‐, site‐, and diastereoselective C−H functionalization of arenes and alkenes with ample scope. The outstanding catalytic activity was reflected by catalyst loadings as low as 0.75 mol %, and the most step‐economical access reported to date to angiotensin II receptor antagonist blockbuster drugs. Mechanistic studies indicated a