Highly Enantioselective Intermolecular Stetter Reactions of β-Aryl Acceptors: α-Ketoester Moiety as Handle for Activation and Synthetic Manipulations
摘要:
The use of beta,gamma-unsaturated-alpha-ketoesters in the intermolecular Stetter reaction furnishes 1,2,5-tricarbonyl compounds in high yield and excellent enantioselectivity. The alpha,delta-diketoesters generated using this methodology serve as useful synthetic building blocks via chemo- and diastereoselective transformations.
Enantioselective Intramolecular Hydroacylation of Unactivated Alkenes: An NHC-Catalyzed Robust and Versatile Formation of Cyclic Chiral Ketones
作者:Daniel Janssen-Müller、Michael Schedler、Mirco Fleige、Constantin G. Daniliuc、Frank Glorius
DOI:10.1002/anie.201412302
日期:2015.10.12
A highly enantioselectiveintramolecular N‐heterocyclic carbene (NHC)‐catalyzed hydroacylation reaction gives access to a range of cyclicketones from unactivated olefin‐substituted aldehydes (up to 99 % ee). Remarkably, aliphatic aldehydes were also transformed efficiently in an NHC‐catalyzed hydroacylation reaction for the first time.
Enantioconvergent Synthesis of Functionalized γ-Butyrolactones via (3 + 2)-Annulation
作者:C. Guy Goodman、Morgan M. Walker、Jeffrey S. Johnson
DOI:10.1021/ja511701j
日期:2015.1.14
A dynamic kineticresolution of β-halo α-keto esters in an asymmetric homoenolate reaction is described. A chiral N-hetereocyclic carbene catalyzes the a3 → d3-umpolung addition of α,β-enals to racemic α-keto esters, forming γ-butyrolactones with threecontiguousstereocenters. The addition occurs with high regio-, diastereo-, and enantiocontrol. This methodology constitutes an intermolecular DKR process
Faster, higher, stronger! The N‐heterocyclic carbene (NHC) catalyzed diastereo‐ and enantioselectivehydroacylation of cyclopropenes affords structurally valuable acylcyclopropanes. A new family of electron‐rich, 2,6‐dimethoxyphenyl‐substituted NHCs induces excellent reactivity and enantioselectivity. Preliminary kinetic studies unambiguously demonstrated the superiority of this family of catalysts