886747-03-1Relevant articles and documents
A relay catalysis strategy for enantioselective nickel-catalyzed migratory hydroarylation forming chiral α-aryl alkylboronates
Chen, Jian,Liang, Yong,Ma, Jiawei,Meng, Lingpu,Zhang, Yao,Zhu, Shaolin
supporting information, p. 3171 - 3188 (2021/11/16)
Ligand-controlled reactivity plays an important role in transition-metal catalysis, enabling a vast number of efficient transformations to be discovered and developed. However, a single ligand is generally used to promote all steps of the catalytic cycle (e.g., oxidative addition, reductive elimination), a requirement that makes ligand design challenging and limits its generality, especially in relay asymmetric transformations. We hypothesized that multiple ligands with a metal center might be used to sequentially promote multiple catalytic steps, thereby combining complementary catalytic reactivities through a simple combination of simple ligands. With this relay catalysis strategy (L/L?), we report here the first highly regio- and enantioselective remote hydroarylation process. By synergistic combination of a known chain-walking ligand and a simple asymmetric cross-coupling ligand with the nickel catalyst, enantioenriched α-aryl alkylboronates could be rapidly obtained as versatile synthetic intermediates through this formal asymmetric remote C(sp3)-H arylation process.
Alkylidene Dihydropyridines As Synthetic Intermediates: Model Studies toward the Synthesis of the Bis(piperidine) Alkaloid Xestoproxamine C
Lansakara, Ashabha I.,Mariappan, S. V. Santhana,Pigge, F. Christopher
, p. 10266 - 10278 (2016/11/17)
Results of model studies demonstrating a stereoselective synthetic route to tricyclic analogues of the bis(piperidine) alkaloid xestoproxamine C are presented. Dearomatization of a tricyclic pyridine derivative to afford an alkylidene dihydropyridine (anhydrobase) intermediate followed by catalytic heterogeneous hydrogenation was used to install the correct relative stereochemistry about the bis(piperidine) ring system. Other key features of these model studies include development of an efficient ring-closing metathesis procedure to prepare macrocyclic derivatives of 3,4-disusbstituted pyridines, intramolecular cyclizations of alkylidene dihydropyridines to establish pyridine-substituted pyrrolidines and piperidines, successful homologation of pyridine-4-carboxaldehydes using formaldehyde dimethyl thioacetal monoxide (FAMSO), and application of B-alkyl Suzuki coupling to assemble substituted pyridines.
