Dataset Information

Functionalized cyclopentenes through a tandem NHC-catalyzed dynamic kinetic resolution and ambient temperature decarboxylation: mechanistic insight and synthetic application.

ABSTRACT: An unusual room temperature ?-lactone decarboxylation facilitated a five-step enantioselective formal synthesis of the cyclopentane core of an estrogen receptor ?-agonist. A computational study probed the underlying factors facilitating unprecedented, rapid decarboxylation. Aryl substitution promotes faster reaction in the retro-[2+2] as a result of conjugative stabilization with the forming olefin. Additionally, the configuration of the ?-ester in these fused ?-lactones leads to differential decarboxylation rates.

SUBMITTER: Cohen DT

PROVIDER: S-EPMC4312178 | biostudies-literature | 2015 Feb

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Functionalized cyclopentenes through a tandem NHC-catalyzed dynamic kinetic resolution and ambient temperature decarboxylation: mechanistic insight and synthetic application.

Cohen Daniel T DT Johnston Ryne C RC Rosson Nicholas T NT Cheong Paul Ha-Yeon PH Scheidt Karl A KA

Chemical communications (Cambridge, England) 20150201 13

An unusual room temperature β-lactone decarboxylation facilitated a five-step enantioselective formal synthesis of the cyclopentane core of an estrogen receptor β-agonist. A computational study probed the underlying factors facilitating unprecedented, rapid decarboxylation. Aryl substitution promotes faster reaction in the retro-[2+2] as a result of conjugative stabilization with the forming olefin. Additionally, the configuration of the α-ester in these fused β-lactones leads to differential de ...[more]

PMID: 25575249

Similar Datasets

Project description:Copper(I) [Cu2(μ-Br)2(tBuImCH2pyCH2L)] n (L = OMe, NEt2, NHtBu) compounds supported by flexible functionalized NHC-based polydentate ligands have been prepared in a one-pot procedure by reacting the corresponding imidazolium salt with an excess of copper powder and Ag2O. An X-ray diffraction analysis has revealed that [Cu2(μ-Br)2(tBuImCH2pyCH2NEt2)] n is a linear coordination polymer formed by bimetallic [Cu(μ-Br)]2 units linked by the lutidine-based NHC-py-NEt2 ligand, which acts as a heteroditopic ligand with a 1κC-2κ2 N,N' coordination mode. We propose that the polymeric compounds break down in the solution into more compact tetranuclear [Cu2(μ-Br)2(tBuImCH2pyCH2L)]2 compounds with a coordination mode identical to the functionalized NHC ligands. These compounds have been found to exhibit high catalytic activity in the Cu-catalyzed azide-alkyne cycloaddition (CuAAC) reaction. In particular, [Cu2(μ-Br)2(tBuImCH2pyCH2NEt2)]2 efficiently catalyzes the click reaction of a range of azides and alkynes, under an inert atmosphere at room temperature in neat conditions at a very low catalyst loading, to quantitatively afford the corresponding 1,4-disubstituted 1,2,3-triazole derivatives in a few minutes. The cycloaddition reaction of benzyl azide to phenylacetylene can be performed at 25-50 ppm catalyst loading by increasing the reaction time and/or temperature. Reactivity studies have shown that the activation of the polynuclear catalyst precursor involves the alkyne deprotonation by the NHC moiety of the polydentate ligand to afford a copper(I)-alkynyl species bearing a functionalized imidazolium ligand. DFT calculations support the participation of the dinuclear species [(CuBr)2(μ-tBuImCH2pyCH2NEt2)], resulting from the fragmentation of the tetranuclear compound, as the catalytically active species. The proposed reaction pathway proceeds through zwitterionic dinuclear intermediates and entails the active participation of both copper atoms, as well as the NHC moiety as an internal base, which activates the reacting alkyne via deprotonation.

Dataset Information

Functionalized cyclopentenes through a tandem NHC-catalyzed dynamic kinetic resolution and ambient temperature decarboxylation: mechanistic insight and synthetic application.

Publications

Functionalized cyclopentenes through a tandem NHC-catalyzed dynamic kinetic resolution and ambient temperature decarboxylation: mechanistic insight and synthetic application.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets