title: Application of a High-Throughput Enantiomeric Excess Optical Assay Involving a Dynamic Covalent Assembly: Parallel Asymmetric Allylation andEeSensing of Homoallylic Alcohols.
abstract: 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 theeevalues 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). Theeevalues 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 reliableeevalues in the CD-based assay. Overall, the nearly 200 reactions whoseeevalues were determined could be quantitated in under two hours. Using a combination of the TLC method to measure yield with the CD-assay to measureeevalues, several trends in reaction conditions were revealed. For example, it was found that the cyclometallated iridium catalyst modified by BINAP andm-nitro-p-cyano-benzoic acid delivered adduct1with the highest levels of enantiomeric enrichment (94%), whereas the corresponding SEGPHOS-modified catalyst gave a comparable yield but loweree(91%). Most importantly, this study shows that supramolecular assemblies can report hundreds ofeevalues in a rapid and reliable fashion to analyze parallel synthesis routines.
authors.affiliation: Department of Chemistry, The University of Texas at Austin, Austin, Texas, 78712.
authors.forename: H H
authors.initials: HH
authors.lastname: Jo
authors.affiliation: Department of Chemistry, The University of Texas at Austin, Austin, Texas, 78712.
authors.forename: X
authors.initials: X
authors.lastname: Gao
authors.affiliation: Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, 350002, P.R. China.
authors.forename: L
authors.initials: L
authors.lastname: You
authors.affiliation: Department of Chemistry, The University of Texas at Austin, Austin, Texas, 78712.
authors.forename: E V
authors.initials: EV
authors.lastname: Anslyn
authors.affiliation: Department of Chemistry, The University of Texas at Austin, Austin, Texas, 78712.
authors.forename: M J
authors.initials: MJ
authors.lastname: Krische