Compounds 2 (M = Mg) obtained in the mono addition of vinylmagnesium bromide to squarates are attractive structural models to determine the influence of complexation between magnesium(II) and the alkoxide group on the regioselectivity of the 1,2- versus 1,4-addition of organomagnesium by complex induced proximity effects (CIPE). The 1,4-addition is observed almost exclusively in the case of vinylmagnesium in THF solution with formation of hydroxyketones type 5, which are always side or minor products in the known reaction of alkenyllithium derivatives. A comparative study on the reactivity of alkenyllithium and magnesiun derivatives is reported. The high regioselectivitity observed in the 1,4-addition of vinylmagnesium bromide is fully understood by computational studies of compounds 2 (M = Mg) at the DFT level with the density functional B3LYP.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1021/jo800617y | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Synthesis of 2-hydroxy analogues of castanospermine, 1-epi-castanospermine and their iminooctitols from sugar-derived lactam.
Carbohydr Res
January 2025
Chemical Sciences and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology (CSIR-NIIST), Thiruvananthapuram, 695019, Kerala, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India. Electronic address:
The synthesis of 2-hydroxy analogues of castanospermine from two new iminooctitols via Mitsunobu cyclization is described. The iminooctitols were derived from the dihydroxylation of an allyl alcohol intermediate, obtained by adding vinylmagnesium bromide to the C6-aldehyde of a protected 1-deoxynojirimycin. An orthogonally protected hemiacetal with silyl group at the C6-hydroxy position and remaining as benzyl ethers, synthesized in four steps from d-glucose, served as a building block in the synthesis of the 1-deoxynojirimycin intermediate.
View Article and Find Full Text PDFSynthesis and catalytic properties of palladium(II) complexes with P,π-chelating ferrocene phosphinoallyl ligands and their non-tethered analogues.
Dalton Trans
May 2024
Department of Inorganic Chemistry, Faculty of Science, Charles University, Hlavova 2030, 128 40 Prague, Czech Republic.
Hybrid phosphines usually combine a phosphine moiety with another heteroatom secondary donor group in their structures while compounds equipped with hydrocarbyl π-donor moieties remain uncommon. This contribution reports the synthesis and structural characterization of the first P/π-allyl-chelating complexes that were obtained using the structurally flexible and redox-active ferrocene unit as the scaffold, . [PdCl(RPfcCHCHCH-η:κ)] (1R; R = Ph and cyclohexyl (Cy); fc = ferrocene-1,1'-diyl).
View Article and Find Full Text PDFStereoselective Synthesis of Heavily Hydroxylated Azepane Iminosugars via Osmium-Catalyzed Tethered Aminohydroxylation.
Org Lett
August 2023
Dipartimento di Chimica "Ugo Schiff" (DICUS), Università di Firenze, Via della Lastruccia 3-13, 50019 Sesto Fiorentino, FI, Italy.
A novel stereoselective synthetic approach to pentahydroxyazepane iminosugars is described. The strategy relies on a key osmium-catalyzed aminohydroxylation reaction of allylic alcohols obtained via addition of vinylmagnesium bromide to a d-mannose-derived aldehyde, which forms the new C-N bond with complete regio- and stereocontrol according to the tethering approach. Subsequent intramolecular reductive amination afforded the desired azepanes.
View Article and Find Full Text PDFStereoselective synthesis of a 4-⍺-glucoside of valienamine and its X-ray structure in complex with Streptomyces coelicolor GlgE1-V279S.
Sci Rep
June 2021
Department of Chemistry and Biochemistry, University of Toledo, Toledo, OH, 43606, USA.
Glycoside hydrolases (GH) are a large family of hydrolytic enzymes found in all domains of life. As such, they control a plethora of normal and pathogenic biological functions. Thus, understanding selective inhibition of GH enzymes at the atomic level can lead to the identification of new classes of therapeutics.
View Article and Find Full Text PDFSynthesis of B-ring-fluorinated (-)-epicatechin gallate derivatives.
Org Biomol Chem
June 2020
Institute for Organic Chemistry and Macromolecular Chemistry, Universität Düsseldorf, Universitätsstr. 1, D-40225 Düsseldorf, Germany.
The synthesis of enantiomerically pure B-ring fluorinated catechin derivatives is presented. In a convergent approach the chromane was obtained by reaction of a lithiated fluoro-resorcine with an optically active epoxide. The latter was prepared from 3,4-difluorobenzaldehyde by reaction with vinylmagnesium bromide followed by Sharpless epoxidation.
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!