Palladium-Catalyzed Enantioselective Addition of Chiral Metal Enolates to In Situ Generated <i>ortho</i>
-Quinone Methides
作者:Fabian Göricke、Christoph Schneider
DOI:10.1002/anie.201809692
日期:2018.11.5
describe herein a conceptually novel, cooperative Brønsted acid/base catalyzed process for the conjugate addition of cyclic β‐keto esters to ortho‐quinone methides both generated in situ. Upon hemiacetalization, densely functionalizedchiral chromans with two adjacent quaternary and additionally a tertiary stereogenic center were obtained with very good diastereoselectivity (up to >95:5 d.r.) and typically
Enantioselective Annulation of α,β-Unsaturated <i>N</i>-Acyliminium Ions with β-Keto Ester Enolates via Cooperative Palladium and Brønsted Acid Catalysis
作者:Cornelius V. Gärtner、Christoph Schneider
DOI:10.1021/acs.orglett.2c01265
日期:2022.5.20
We herein report a cooperative palladium- and Brønsted acid-catalyzed strategy toward the first enantioselective annulation of in situ generated α,β-unsaturated N-acyliminium ions with chiral metal enolates. Novel polycyclic oxoisoindoles featuring three contiguous stereogenic centers have been obtained with typically good yields, outstanding enantiocontrol, and moderate to good diastereoselectivity
Enantioselective 1,6-Addition of β-Ketoester Enolates to <i>In Situ</i> Generated <i>para</i>-Quinone Methides Enabled by Cooperative Palladium and Brønsted Acid Catalysis
作者:Cornelius V. Gärtner、Christoph Schneider
DOI:10.1021/acs.orglett.2c04127
日期:2023.1.20
We report herein an asymmetric cooperative process for the enantioselective 1,6-addition of β-ketoesters to in situ generated para-quinone methides with chiral Pd–aqua complexes as mixed Brønsted acid–base catalysts. Excellent yields, outstanding enantiocontrol, and good diastereoselectivity across a broad substrate range are highlights of this transformation. The utility of this reaction is further
Optimized stereoselective and scalable synthesis of five‐membered cyclic <i>trans</i>‐β‐amino acid building blocks via reductive amination
作者:Jungwoo Hong、Wonchul Lee、Hee‐Seung Lee
DOI:10.1002/bkcs.12786
日期:2023.12
We present an optimized method for the stereoselective synthesis of five-membered alicyclic and heterocyclic trans-β-amino acidderivatives. The process involves a reductive amination of β-keto esters using chiral auxiliary amines, with formic acid acting as a facilitator for rapid, diastereoselective reductions under gentle conditions. Our approach notably enhances isolated yields and permits the
Enantioselective (3+2)-Annulation of β-Keto Esters with Azoalkenes towards Bicyclic Dihydropyrroles via Cooperative Palladium and Brønsted Acid Catalysis
作者:Christoph Schneider、Till Friedmann、Daniel A. Mireles-Chávez、Frederik L. Walter
DOI:10.1055/a-2210-0973
日期:——
A cooperative catalytic process through palladium and Brønstedacid activation is developed for the conjugate addition of cyclic β-keto esters to azoalkenes directly followed by hemiaminal formation upon cyclization. This transformation is enabled by utilizing chiral Pd-aqua complexes as combined Brønsted acid–base catalysts. Thus, bicyclic and highly functionalized dihydropyrroles with two contiguous