Transition-metal-catalyzed cross-coupling reactions have fundamentally revolutionized organic synthesis, empowering the otherwise difficult to achieve products with rapid and convenient accesses alongside excellent yields. Within these reactions, ligands often play a critical role in specifically and effectively advocating the corresponding catalysis. Consequently, a myriad of ligands have been created and applied to make a fine tuning of electronic and steric effect of catalysts, remarkably promoting catalytic efficiency and applicability. The "mixed-ligand" concept has recently emerged; by combining and capitalizing on the superiority of each individual ligand already available, an expedient way can be achieved to reach a larger extent of catalytic diversity and efficacy. Given the availability of a wealth of ligands, it is reasonable to have great expectations for the original application of mixed-ligand catalytic systems and their important value in organic synthesis.
High-throughput chemistry (HTC) and direct-to-biology (D2B) platforms allow for plate-based compound synthesis and biological evaluation of crude mixtures in cellular assays. The rise of these workflows has rapidly accelerated drug-discovery programs in the field of targeted protein degradation (TPD) in recent years by removing a key bottleneck of compound purification. However, the number of chemical transformations amenable to this methodology remain minimal, leading to limitations in the exploration of chemical space using existing library-based approaches.
Department of Spine Surgery and Musculoskeletal Tumor, Zhongnan Hospital of Wuhan University, School of Pharmaceutical Sciences, Wuhan University Wuhan 430071 China
Replacement of a carbonyl group with fluorinated bioisostere (, CF[double bond, length as m-dash]C) has been adopted as a key tactical strategy in drug design and development, which typically improves potency and modulates lipophilicity while maintaining biological activity. Consequently, new -difluoroalkenation reactions have undoubtedly accelerated this shift, and conceptually innovative practices would be of great benefit to medicinal chemists. Here we describe an expeditous protocol for the direct assembly of furan-substituted -difluoroalkenes PFTB-promoted cross-coupling of ene-yne-ketones and difluorocarbene.
We describe herein the design and synthesis of a new class of dialkylarylphosphine ligands incorporating a Lewis-basic urea subunit. The ligand synthesis consisted of six linear steps and was enabled by the discovery of a new N-to-N alkyl migration reaction. This new series of dialkylarylphosphine urea ligands were applied in common palladium-catalyzed cross-coupling reactions for the formation of carbon-carbon and carbon-nitrogen bonds in moderate to high yields.
Nickel-catalyzed cross-electrophile coupling (XEC) reactions of (hetero)aryl electrophiles represent appealing alternatives to palladium-catalyzed methods for biaryl synthesis, but they often generate significant quantities of homocoupling and/or proto-dehalogenation side products. In this study, an informer library of heteroaryl chloride and aryl bromide coupling partners is used to identify Ni-catalyzed XEC conditions that access high selectivity for the cross-product when using equimolar quantities of the two substrates. Two different catalyst systems are identified that show complementary scope and broad functional-group tolerance, and time-course data suggest that the two methods follow different mechanisms.
We present a tandem aza-Heck/Suzuki cross-coupling reaction of -phenyl hydroxamic ethers with readily available arylboronic and alkenyl boronic acids. This protocol is enabled by a palladium catalyst paired with chiral phosphoramidite ligands, particularly under mild reaction conditions, yielding efficient and succinct synthetic routes to chiral isoindolinones with high enantioselectivity. Furthermore, this reaction exhibits excellent functional group compatibility and a rich diversity of subsequent transformations.
