alpha'-Hydroxy enones react with dienes in the presence of (S,S)-[Cu(tBu-box)](OTf)2 or (S,S)-[Cu(tBu-box)](SbF6)2 (2 to 10 mol %) to afford the corresponding Diels-Alder adducts in high yield and selectivity. Isomeric ratios (regioselectivity, endo/exo or cis/trans) of up to >99:1 and ee values of up to >99% are obtained. Significantly, difficult dienes such as isoprene, 2,3-dimethyl butadiene and piperylene behave satisfactorily. Subsequent oxidative cleavage of the ketol in the resulting cycloadducts by treatment with cerium ammonium nitrate (CAN) yields the corresponding enantiopure carboxylic acids. Alternatively, carbonyl addition and subsequent diol cleavage with CAN produces the corresponding ketone adducts.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1021/ja0368002 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Direct Deoxygenation of α-Hydroxy and α,β-Dihydroxy Ketones Using a Silyl Lithium Reagent.
J Org Chem
October 2023
Organic Chemistry Division, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune, Maharashtra 411008, India.
A reliable method for the one-step direct deoxygenation of α-hydroxy ketones has been developed using a silyl lithium reagent and acetic anhydride. The method is metal-catalyst-free and does not require prefunctionalization of the hydroxy group prior to its removal. Deoxygenation of different primary, secondary, and tertiary alcohols was carried out with up to 98% isolated yield.
View Article and Find Full Text PDFDevelopment of an α'-hydroxy enone for the aminocatalytic asymmetric formal conjugate addition of aldehydes to acrylates, vinyl ketones and acrolein.
Org Biomol Chem
June 2023
Departamento de Química Orgánica I. Universidad del País Vasco UPV/EHU. Manuel Lardizabal 3, 20018-San Sebastián, Spain.
Aminocatalytic asymmetric conjugate addition of aldehydes to Michael acceptors is a well established C-C bond forming methodology. However, various acrylic-type acceptors, including acrylic acid derivatives and acrolein, remain reluctant. Here we demonstrate that the internal H-bonding self-activation in α'-hydroxy enones allows them to react smoothly with enolizable aldehydes using commercially available aminocatalysts to afford adducts in good yields and high enantioselectivity.
View Article and Find Full Text PDFA dinickel-catalyzed three-component cycloaddition of vinylidenes.
Chem Sci
September 2022
Department of Chemistry, Purdue University West Lafayette Indiana 47907 USA
A dinickel catalyst promotes the [2 + 2 + 1]-cycloaddition of two aldehyde equivalents and a vinylidene. The resulting methylenedioxolane products can be deprotected in one pot under acidic conditions to reveal α-hydroxy ketones. This method provides convenient access to unsymmetrical alkyl-substituted α-hydroxy ketones, which are challenging to synthesize selectively using cross-benzoin reactions.
View Article and Find Full Text PDFHighly Diastereoselective Intramolecular Asymmetric Oxidopyrylium-olefin [5 + 2] Cycloaddition and Synthesis of 8-Oxabicyclo[3.2.1]oct-3-enone Containing Ring Systems.
J Org Chem
June 2021
Department of Chemistry and Department of Medicinal Chemistry, Purdue University, 560 Oval Drive, West Lafayette, Indiana 47907, United States.
We have the investigated base mediated asymmetric intramolecular oxidopyrylium-alkene [5 + 2]-cycloaddition reaction which resulted in the synthesis of functionalized tricyclic ring systems containing an 8-oxabicyclo[3.2.1]octane core.
View Article and Find Full Text PDFβ-Selective Aroylation of Activated Alkenes by Photoredox Catalysis.
Angew Chem Int Ed Engl
May 2019
Department of Chemistry and Institute of Chemical Biology and Drug Discovery, The State University of New York at Stony Brook, Stony Brook, NY, 11794, USA.
Late-stage synthesis of α,β-unsaturated aryl ketones remains an unmet challenge in organic synthesis. Reported herein is a photocatalytic non-chain-radical aroyl chlorination of alkenes by a 1,3-chlorine atom shift to form β-chloroketones as masked enones that liberate the desired enones upon workup. This strategy suppresses side reactions of the enone products.
View Article and Find Full Text PDFWant 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!