Cobalt-Catalyzed Allylic C(sp<sup>3</sup>)–H Carboxylation with CO<sub>2</sub>
作者:Kenichi Michigami、Tsuyoshi Mita、Yoshihiro Sato
DOI:10.1021/jacs.7b02775
日期:2017.5.3
tolerability, so that selective addition to CO2 occurred in the presence of other carbonyl groups such as amide, ester, and ketone. Since styrylacetic acidderivatives can be readily converted into optically active γ-butyrolactones through Sharpless asymmetric dihydroxylation, this allylic C(sp3)-H carboxylation showcases a facile synthesis of γ-butyrolactones from simple allylarenes via short steps.
We report herein a direct method to synthesize 4-aryl-3-butenoic acid through a carboxylic-acid-directed oxidative Heck reaction. The various 4-aryl-3-butenoic acids are easily prepared in moderate to good yields. In view of the promising bioactivity of 4-phenyl-3-butenoic acid previously reported, its derivatives reported here may be bioactive.
Vinyldiazo compounds undergo a thermal electrocyclization to form pyrazoles in yields of up to 95%. The reactions are operationally simple, use readily available starting materials, require no intervention of a catalyst, and enable the synthesis of mono-, di- and tri-substituted pyrazoles. With the ability to produce highly substituted pyrazoles and the flexibility in installing various types of substituents
A Chiral Electrophilic Selenium Catalyst for Highly Enantioselective Oxidative Cyclization
作者:Yu Kawamata、Takuya Hashimoto、Keiji Maruoka
DOI:10.1021/jacs.6b01462
日期:2016.4.27
Chiral electrophilic selenium catalysts have been applied to catalytic asymmetric transformations of alkenes over the past two decades. However, highlyenantioselective reactions with a broad substrate scope have not yet been developed. We report the first successful example of this reaction employing a catalyst based on a rigid indanol scaffold, which can be easily synthesized from a commercially