In 2018,Chen, Tie-Gen; Barton, Lisa M.; Lin, Yutong; Tsien, Jet; Kossler, David; Bastida, Inaki; Asai, Shota; Bi, Cheng; Chen, Jason S.; Shan, Mingde; Fang, Hui; Fang, Francis G.; Choi, Hyeong-wook; Hawkins, Lynn; Qin, Tian; Baran, Phil S. published 《Building C(sp3)-rich complexity by combining cycloaddition and C-C cross-coupling reactions》.Nature (London, United Kingdom) published the findings.Name: 5-Bromo-2-chloropyridine The information in the text is summarized as follows:
Prized for their ability to rapidly generate chem. complexity by building new ring systems and stereocentres, cycloaddition reactions have featured in numerous total syntheses and are a key component in the education of chem. students. Similarly, carbon-carbon (C-C) cross-coupling methods are integral to synthesis because of their programmability, modularity and reliability. Within the area of drug discovery, an overreliance on cross-coupling has led to a disproportionate representation of flat architectures that are rich in carbon atoms with orbitals hybridized in an sp2 manner. Despite the ability of cycloadditions to introduce multiple carbon sp3 centers in a single step, they are less used. This is probably because of their lack of modularity, stemming from the idiosyncratic steric and electronic rules for each specific type of cycloaddition Here we demonstrate a strategy for combining the optimal features of these two chem. transformations into one simple sequence, to enable the modular, enantioselective, scalable and programmable preparation of useful building blocks, natural products and lead scaffolds for drug discovery. The results came from multiple reactions, including the reaction of 5-Bromo-2-chloropyridine(cas: 53939-30-3Name: 5-Bromo-2-chloropyridine)
5-Bromo-2-chloropyridine(cas: 53939-30-3) belongs to pyridine. Pyridine is very deactivated towards electrophilic substitution with respect to benzene. For this reason classical formylation, using methods such as the Gattermann or Vilsmeier reactions, are not generally successful. Name: 5-Bromo-2-chloropyridine