Overriding Intrinsic Reactivity in Aliphatic C−H Oxidation: Preferential C3/C4 Oxidation of Aliphatic Ammonium Substrates
作者:Melina Knezevic、Michael Heilmann、Giovanni Maria Piccini、Konrad Tiefenbacher
DOI:10.1002/anie.202004242
日期:2020.7.20
The site‐selective C−H oxidation of unactivated positions in aliphatic ammonium chains poses a tremendous synthetic challenge, for which a solution has not yet been found. Here, we report the preferential oxidation of the strongly deactivated C3/C4 positions of aliphatic ammonium substrates by employing a novel supramolecular catalyst. This chimeric catalyst was synthesized by linking the well‐explored
Acyclic Congener of Cucurbituril: Synthesis and Recognition Properties
作者:Christopher A. Burnett、Dariusz Witt、James C. Fettinger、Lyle Isaacs
DOI:10.1021/jo034399w
日期:2003.8.1
inability to access specific cucurbit[n]uril homologues, derivatives, and analogues by straightforward tailor-made synthetic procedures. In this paper, we explore an approach that circumvents the challenges posed by the tailor-made synthesis of macrocyclic CB[n] by preparing 1, which functions as an acyclic CB[6] congener. The o-xylylene connections to the glycoluril rings preorganize 1 into the (a
Diastereoselective Formation of Methylene-Bridged Glycoluril Dimers
作者:Dariusz Witt、Jason Lagona、Fehmi Damkaci、James C. Fettinger、Lyle Isaacs
DOI:10.1021/ol991382k
日期:2000.3.1
The acid-catalyzed formation of methylene-bridged glycoluril dimers yields the C-2v-diastereomer selectively. Product resubmission experiments establish that the selectivity is the result of thermodynamic control. A modified synthetic route is presented that allows for the preparation of unsymmetrically substituted dimers, We present the X-ray crystal structures of both diastereomers, This class of compounds is useful for studies of self-assembly in aqueous solution.