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Asymmetric Ir-catalyzed C–C coupling of primary alcohols with allyl-acetates, as described by Krische, to form chiral secondary homo-allylic alcohols were performed in parallel as a means to optimize the ee values thereof. Specifically, approximately 400 examples of this reaction were performed by varying the catalyst, added acids and bases, and starting reactants, to form 4-phenyl-1-butene-4-ol (1). The ee values for the transformations were determined in a high-throughput fashion using a 4-component assembly that creates a circular dichroism signal indicative of the extent of asymmetric induction. Further, a parallel and rapid quantitative TLC method measures the yield of each reaction, revealing which reactions give reliable ee values in the CD-based assay. Overall, the nearly 200 reactions whose ee values were determined could be quantitated in under two hours. Using a combination of the TLC method to measure yield with the CD-assay to measure ee values, several trends in reaction conditions were revealed. For example, it was found that the cyclometalated iridium catalyst modified by BINAP and m-nitro-p-cyano-benzoic acid delivered adduct 1 with the highest levels of enantiomeric enrichment (94%), whereas the corresponding SEGPHOS-modified catalyst gave a comparable yield but lower ee (91%). Most importantly, this study shows that supramolecular assemblies can report hundreds of ee values in a rapid and reliable fashion to analyze parallel synthesis routines. 相似文献
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Michael J. Krische Jean-Marie Lehn Natalie Kyritsakas Jean Fischer ElinaKaroliina Wegelius MaijaJohanna Nissinen Kari Rissanen 《Helvetica chimica acta》1998,81(11):1921-1930
The programmed self-association of 2,2′-diamino-4,4′-dialkoxy-5,5′-bipyrimidines allows for the de novo construction of alkoxy-functionalized H-bonded ribbons and sheets as evidenced by X-ray crystallographic analysis. The data provide insight into the interplay of the different structural and interactional features of the molecular components to the generation of the supramolecular assembly. Hydrophobicity of the didodecyl side chains of 4c leads to the dominance of the H-bonding factor, resulting in the formation of a fully interconnected array. These results define the utility of the of 2,2′-diamino-4,4′-dialkoxy-5,5′-bipyrimidines as a potential scaffold for the attachment of electro- or photochemically active alkoxy residues for self-assembled functional supramolecular materials. 相似文献
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Hiroki Sato Michelle A. Blemker Garrett Hellinghausen Prof. Daniel W. Armstrong Jordan W. Nafie Prof. Sean T. Roberts Prof. Michael J. Krische 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(37):8719-8724
Cyclometalation of a triple helical N-doped phenylene cage prepared by ruthenium(0)-catalyzed diol–diene benzannulation delivers a chiral, conformationally constrained Ir(ppy)3 analogue. Like the parent complex, fac-Ir(ppy)3, the iridium-containing PAH-cage is phosphorescent, but displays enhanced resistance to oxygen quenching. 相似文献
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Hassan A Montgomery TP Krische MJ 《Chemical communications (Cambridge, England)》2012,48(39):4692-4694
Commercially available (2-fluoro)allyl chloride serves as an efficient allyl donor in highly enantioselective iridium catalyzed carbonyl (2-fluoro)allylations from the alcohol or aldehyde oxidation level via transfer hydrogenation. Diastereoselective Crabtree hydrogenation of the resulting homoallylic alcohols provides syn-3-fluoro-1-alcohols. 相似文献