Palladium-Catalyzed Intermolecular Alkene Carboacylation via Ester C–O Bond Activation
作者:Haley K. Banovetz、Kevin L. Vickerman、Colton M. David、Melisa Alkan、Levi M. Stanley
DOI:10.1021/acs.orglett.1c00940
日期:2021.5.7
We report palladium-catalyzed intermolecular carboacylation of alkenes with ester electrophiles and tetraarylborate nucleophiles. Bicyclic alkenes react with a variety of pentafluorophenyl benzoate and alkanoate esters and sodium tetraarylborates to form ketone products in ≤99% yields. These reactions occur in the absence of a directing group and demonstrate esters are competent acyl electrophiles
Intermolecular Dearomatization of Naphthalene Derivatives by Photoredox‐Catalyzed 1,2‐Hydroalkylation
作者:Yuan‐Zheng Cheng、Xu‐Lun Huang、Wei‐Hui Zhuang、Qing‐Ru Zhao、Xiao Zhang、Tian‐Sheng Mei、Shu‐Li You
DOI:10.1002/anie.202008358
日期:2020.10.5
visible‐light photoredoxcatalysis. With an organic photocatalyst, a series of multi‐substituted 1,2‐dihydronaphthalenes are obtained in good‐to‐excellent yields. Intriguingly, by tuning the substituents at the C2 position of naphthalenes, formal dearomative [3+2] cycloadditions occur exclusively via a hydroalkylative dearomatization–cyclization sequence. This overall redox‐neutral method features mild
The use of self-complementary structures in replication experiments is discussed, and a second generation of self-replicating molecules is introduced. Key design elements of the new system are described, specifically a high affinity (K-a similar to 10(5) M(-1) in CDCl3) between the two complementary reactive components and the careful placement of nucleophilic and electrophilic centers within the system. These considerations preclude intramolecular reactions within two-component complexes, thus minimizing undesirable background reactions. Autocatalysis is observed in the new systems, and by using appropriate control experiments the autocatalysis is traced to template effects.
Evidence against an Alternative Mechanism for a Self-Replicating System
作者:Edward A. Wintner、Belinda Tsao、Julius Rebek
DOI:10.1021/jo00129a046
日期:1995.12
A recent paper by Menger et al. described experimental and computational work related to our self-replicating system and concluded that amide catalysis-either external or internal-is the cause of observed rate enhancements. Herein we show that the proposal of Menger et al. is inconsistent with published data, that their conclusions overreach the data afforded by their experiments, and that the step which they modeled is likely irrelevant to the autocatalytic nature of the system. We present new results and a refined mechanism in which the transition state is stabilized not by amides but by template-based recognition, the hallmark of self-replicating systems.
Conn, M. Morgan; Wintner, Edward A.; Rebek, Julius, Angewandte Chemie, 1994, vol. 106, # 15/16, p. 1665 - 1667
作者:Conn, M. Morgan、Wintner, Edward A.、Rebek, Julius