Catalytic Enantioselective Intramolecular Oxa-Michael Reaction to α,β-Unsaturated Esters and Amides.

J Am Chem Soc

Department of Chemistry, Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, OX1 3TA Oxford, U.K.

Published: June 2023

A bifunctional iminophosphorane (BIMP)-catalyzed, enantioselective intramolecular oxa-Michael reaction of alcohols to tethered, low electrophilicity Michael acceptors is described. Improved reactivity over previous reports (1 day vs 7 days), excellent yields (up to 99%), and enantiomeric ratios (up to 99.5:0.5 er) are demonstrated. The broad reaction scope, enabled by catalyst modularity and tunability, includes substituted tetrahydrofurans (THFs) and tetrahydropyrans (THPs), oxaspirocycles, sugar and natural product derivatives, dihydro-(iso)-benzofurans, and iso-chromans. A state-of-the-art computational study revealed that the enantioselectivity originates from the presence of several favorable intermolecular hydrogen bonds between the BIMP catalyst and the substrate that induce stabilizing electrostatic and orbital interactions. The newly developed catalytic enantioselective approach was carried out on multigram scale, and multiple Michael adducts were further derivatized to an array of useful building blocks, providing access to enantioenriched biologically active molecules and natural products.

Download full-text PDF

Source
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC10273320PMC
http://dx.doi.org/10.1021/jacs.3c03182DOI Listing

Publication Analysis

Top Keywords

catalytic enantioselective
8
enantioselective intramolecular
8
intramolecular oxa-michael
8
oxa-michael reaction
8
reaction αβ-unsaturated
4
αβ-unsaturated esters
4
esters amides
4
amides bifunctional
4
bifunctional iminophosphorane
4
iminophosphorane bimp-catalyzed
4

Similar Publications

Asymmetric Functionalization Harnessing Radical-Mediated Functional-Group Migration.

Angew Chem Int Ed Engl

January 2025

Shanghai Jiao Tong University, Frontiers Science Center for Transformative Molecules, 800 Dongchuan Road, 200240, Shanghai, CHINA.

Along with the renaissance of radical chemistry, the past decade has witnessed rapid development in radical-mediated rearrangement reactions. A wide diversity of radical approaches harnessing functional-group migration (FGM) have been devised to enhance both synthetic efficiency and molecular complexity. However, the application of FGM reactions to construct stereogenic centers remains underexplored owing to the inherent challenges of asymmetric radical reactions.

View Article and Find Full Text PDF

Catalytic asymmetric photocycloaddition reactions mediated by enantioselective radical approaches.

Chem Soc Rev

January 2025

Pingyuan Laboratory, School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, 453007, Henan, P. R. China.

The use of olefins in the construction of cyclic compounds represents a powerful strategy for advancing the pharmaceutical industry. Photocycloaddition has attracted significant interest from chemists due to its ability to exploit simple and readily available olefins along with their reaction patterns under mild conditions. Moreover, the sustainable and versatile pathways for generating highly reactive intermediates can greatly enrich both substrate diversity and reaction patterns.

View Article and Find Full Text PDF

Recently, nickel catalysts have garnered considerable attention for their efficacy and versatility in asymmetric catalysis, attributed to their distinctive properties. However, the use of cost-effective and sustainable divalent nickel catalysts in C-H activation/asymmetric alkene insertion poses significant challenges due to the intricate control of stereochemistry in the transformation of the tetracoordinate C-Ni(II) intermediate. Herein, we report a Ni(II)-catalyzed enantioselective C-H/N-H annulation with oxabicyclic alkenes.

View Article and Find Full Text PDF

Multicomponent reactions (MCRs), highly sought-after methods to produce atom-, step-, and energy-economic organic syntheses, have been developed extensively. However, catalytic asymmetric MCRs, especially those involving radical species, remain largely unexplored owing to the difficulty in stereoselectively regulating the extraordinarily high reactivity of open-shell radical species. Herein, we report a conceptually novel catalytic asymmetric three-component radical cascade reaction of readily accessible glycine esters, α-bromo carbonyl compounds and 2-vinylcyclopropyl ketones via synergistic photoredox/Brønsted acid catalysis, in which three sequential C-C (σ/π/σ) bond-forming events occurred through a radical addition/ring-opening/radical-radical coupling protocol, affording an array of valuable enantioenriched unnatural α-amino acid derivatives bearing two contiguous stereogenic centers and an alkene moiety in moderate to good yield with high diastereoselectivity, excellent enantioselectivity and good -dominated geometry under mild reaction conditions.

View Article and Find Full Text PDF

A stereochemical model and origins of selectivity for the rhodium-catalyzed hydroselenation of styrene.

Dalton Trans

January 2025

Chongqing Key Laboratory of Green Catalysis Materials and Technology, College of Chemistry, Chongqing Normal University, Chongqing 401331, China.

A deeper understanding of the mechanisms underlying transition metal-catalyzed transformation is crucial for developing innovative strategies to synthesize chiral organoselenium compounds. In this study, we developed and investigated a three-layer chirality relay model for the rhodium-catalyzed asymmetric hydroselenation of alkenes through density functional theory (DFT) calculations. In the back layer of this model, the four bulky substituents on the phosphorus atom of the bidentate chiral MeO-BIPHEP ligand were positioned on axial and equatorial bonds, thereby influencing the configuration of the middle layer.

View Article and Find Full Text PDF

Want AI Summaries of new PubMed Abstracts delivered to your In-box?

Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!