作者:Emily R. T. Robinson、Charlene Fallan、Carmen Simal、Alexandra M. Z. Slawin、Andrew D. Smith
DOI:10.1039/c3sc50199j
日期:——
The asymmetric annulation of a range of α,β-unsaturated acyl ammonium intermediates, formed from isothiourea HBTM 2.1 and anhydrides with either 1,3-dicarbonyls, β-ketoesters or azaaryl ketones gives either functionalised esters (upon ring opening), dihydropyranones or dihydropyridones in good yields (up to 93%) and high enantioselectivity (up to 97% ee).
Aerobic Oxidation/Annulation Cascades through Synergistic Catalysis of RuCl<sub>3</sub>
and N-Heterocyclic Carbenes
作者:Qian Wang、Jiean Chen、Yong Huang
DOI:10.1002/chem.201803254
日期:2018.9.3
Cooperative catalysis combining a transition metal with an N‐heterocyclic carbene is challenging due to strong binding of NHCstowards late transition metals. We report the first example of synergistic catalysis by a chiral NHC and a coordinatively unsaturated ruthenium compound. RuCl3 was found to mediate efficient aerobic oxidation of homoenolates generated from enals and the N‐heterocyclic carbene
Asymmetric aerobic oxidative NHC-catalysed synthesis of dihydropyranones utilising a system of electron transfer mediators
作者:A. Axelsson、E. Hammarvid、L. Ta、H. Sundén
DOI:10.1039/c6cc06060a
日期:——
Enantioselective synthesis of dihydropyranones via aerobic multistep electron transfer NHC catalysis. Selective introduction of O2 as the terminal oxidant.
Direct β-Activation of Saturated Aldehydes to Formal Michael Acceptors through Oxidative NHC Catalysis
作者:Junming Mo、Liang Shen、Yonggui Robin Chi
DOI:10.1002/anie.201302152
日期:2013.8.12
mediated by N‐heterocyclic carbenes (NHCs) enables the direct β‐carbon functionalization of saturated aldehydes (see scheme). The reaction proceeds through two sequential oxidative steps to generate α,β‐unsaturated triazolium ester equivalents as formal Michael acceptors, which react with 1,3‐diketones and β‐ketone esters in an enantioselective manner.
Direct Activation of β-sp<sup>3</sup>-Carbons of Saturated Carboxylic Esters as Electrophilic Carbons via Oxidative Carbene Catalysis
作者:Bin Liu、Weihong Wang、Ruoyan Huang、Jiekuan Yan、Jichang Wu、Wei Xue、Song Yang、Zhichao Jin、Yonggui Robin Chi
DOI:10.1021/acs.orglett.7b03650
日期:2018.1.5
An N-heterocyclic carbene-catalyzed oxidative LUMO activation of the β-cabons of saturated carboxylic esters is disclosed. This approach allows for efficient asymmetric access to lactams and lactones by directly installing functional groups to the typically inert β-sp3 carbons of saturated esters. The use of HOBt as an additive was found to significantly improve both yields and enantioselectivities