Discovery of a new palladacycle precatalyst and its applications to C–O coupling reactions between electron-deficient phenols and functionalized heteroaryl chlorides

Umpolung Synthesis of Pyridyl Ethers by BiV -Mediated O-Arylation of Pyridones

We report that O-selective arylation of 2- and 4-pyridones with arylboronic acids is affected by a modular, bismacycle-based system. The utility of this umpolung approach to pyridyl ethers, which is complementary to conventional methods based on S_N Ar or cross-coupling, is demonstrated through the concise synthesis of Ki6783 and picolinafen, and the formal synthesis of cabozantib and golvatinib. Computational investigations reveal that arylation proceeds in a concerted fashion via a 5-membered transition state. The kinetically-controlled regioselectivity for O-arylation-which is reversed relative to previous Bi^V -mediated pyridone arylations-is attributed primarily to the geometric constraints imposed by the bismacyclic scaffold.

Palladium(ii) complexes of N,N-diphenylacetamide based thio/selenoethers and flower shaped Pd16S7and prismatic Pd17Se15nano-particles tailored as catalysts for C–C and C–O coupling

Pd₁₆S₇/Pd₁₇Se₁₅NPs of shapes unknown hitherto and their Pd precursors (0.0001 mol%) are efficient/reusable catalysts for Suzuki–Miyaura/C–O coupling.