Heterogeneous or homogeneous? A case study involving palladium-containing perovskites in the Suzuki reaction

The utility of a series of palladium-containing perovskite catalysts in the Suzuki reaction is described; turnover numbers of up to 400,000 are reported. A detailed investigation into the mode of action of these catalysts encompassing kinetic studies, catalyst poisoning, microscopy and three-phase tests demonstrate that these heterogeneous materials are pre-catalysts that operate by a solution-phase mechanism. © 2005 Wiley-VCH Verlag GmbH and Co. KGaA

Palladium-containing perovskites: recoverable and reuseable catalysts for Suzuki couplings.

Palladium-containing perovskites (LaFe0.57Co0.38Pd0.05O3) have been exploited as recoverable and reuseable catalysts in Suzuki coupling reactions; residual levels of Pd after removal of the catalyst by filtration are low (2 ppm) despite evidence that the reaction is occurring via a homogeneous process

Synthesis and applications of highly functionalized 1-halo-3-substituted bicyclo[1.1.1]pentanes

Bicyclo[1.1.1]pentanes (BCPs) are important bioisosteres of 1,4-disubstituted arenes, tert-butyl and acetylenic groups that can impart physicochemical benefits on drug candidates. Here we describe the synthesis of BCPs bearing carbon and halogen substituents under exceptionally mild reaction conditions, via triethylborane-initiated atom-transfer radical addition ring-opening of tricyclo[1.1.1.01,3]pentane (TCP) with alkyl halides. This chemistry displays broad substrate scope and functional group tolerance, enabling application to BCP analogues of biologically-relevant targets such as peptides, nucleosides, and pharmaceuticals. The BCP halide products can be converted to the parent phenyl/tert-butyl surrogates through triethylborane-promoted dehalogenation, or to other derivatives including carbonyls, alcohols, and heterocycles