[EN] TRIAZOLIUM CARBENE CATALYSTS AND PROCESSES FOR ASYMMETRIC CARBON-CARBON BOND FORMATION [FR] CATALYSEURS À BASE DE CARBÈNE DE TRIAZOLIUM ET PROCÉDÉS POUR FORMER DES LIAISONS CARBONE-CARBONE ASYMÉTRIQUES
Catalytic Asymmetric Intermolecular Stetter Reaction of Heterocyclic Aldehydes with Nitroalkenes: Backbone Fluorination Improves Selectivity
作者:Daniel A. DiRocco、Kevin M. Oberg、Derek M. Dalton、Tomislav Rovis
DOI:10.1021/ja904375q
日期:2009.8.12
The catalyticasymmetricintermolecularStetterreaction of heterocyclic aldehydes and nitroalkenes has been developed. We have identified a strong stereoelectronic effect on catalyst structure when a fluorine substituent is placed in the backbone. X-ray structure analysis provides evidence that hyperconjugative effects are responsible for a change in conformation in the azolium precatalyst. This new
TRIAZOLIUM CARBENE CATALYSTS AND PROCESSES FOR ASYMMETRIC CARBON-CARBON BOND FORMATION
申请人:Rovis Tomislav
公开号:US20130116445A1
公开(公告)日:2013-05-09
Provided herein are chiral triazolium catalysts useful for asymmetric C—C bond formation and processes for their preparation. Also provided are synthetic reactions in which these catalysts are used, in particular, in asymmetric C—C bond formation.
Quantum Mechanical Investigation of the Effect of Catalyst Fluorination in the Intermolecular Asymmetric Stetter Reaction
作者:Joann M. Um、Daniel A. DiRocco、Elizabeth L. Noey、Tomislav Rovis、K. N. Houk
DOI:10.1021/ja202444g
日期:2011.7.27
The asymmetric intermolecular Stetter reaction was investigated using the B3LYP and M06-2X functionals. Fluorination of a triazolium bicyclic catalyst had been found to significantly influence reaction yields and enantiomeric ratios. Computations indicate that the improved reactivity of the fluorinated catalyst is due to better electrostatic interactions between the nitroalkene and catalyst. Computational investigations of preferred conformations of the ground state catalyst and acyl anion equivalent, and the transition structures leading to both enantiomers of the products, are reported.