Synthesis, characterisation and reactivity studies of chiral β-diketiminate-like supported aluminium Lewis acid
Deepamali Dissanayake1, Craig Forsyth1, Dragoslav Vidović1
1School of Chemistry, Monash University, Wellington Rd, Clayton VIC 3800, Australia. drasko.vidovic@monash.edu.
Abstract:
Synthesis and characterisation of several chiral, oxazoline containing β-diketiminate type ligand supported-aluminium compounds are reported. Together with 1 equiv. of Na(BArCl4) (ArCl = 3,5-Cl2-C6H3), these chiral Lewis acid complexes, which possess an "achiral end" and "chiral end" have been successfully utilised as catalysts in asymmetric Diels-Alder reactions of 1,3-cyclohexadiene and several different chalcones. Systematic increase in the steric demand of the ligand's "achiral end" of these complexes resulted in enhanced enantioinduction for the cyclisation of 1,3-cyclohexadiene and chalcone. Further structural modifications of the "chiral end" clearly established that having a tert-butyl group connected to the stereogenic centre of the oxazoline fragment yielded the highest enantioselectivity value for the examined cyclisation. A substrate scope was then expanded using several different dienophiles (i.e. chalcones) generating an enantiomeric excess range of 24-68%.
More Related Videos
10:17Efficient Construction of Drug-like Bispirocyclic Scaffolds Via Organocatalytic Cycloadditions of α-Imino γ-Lactones and Alkylidene Pyrazolones
Published on: February 7, 2019
06:46Facile Preparation of 2Z,4E-Dienamides by the Olefination of Electron-deficient Alkenes with Allyl Acetate
Published on: June 21, 2017
Related Concept Videos
[4+2] Cycloaddition of Conjugated Dienes: Diels–Alder Reaction
Diels–Alder Reaction Forming Cyclic Products: Stereochemistry
Diels–Alder Reaction: Characteristics of Dienes
Characteristics of the diene
Conformation
The simplest example of a diene is 1,3-butadiene, an acyclic conjugated π system. At room temperature, the molecule exists as a mixture of s-cis and s-trans conformers by virtue of rotation around the carbon–carbon single bond. Although the s-trans isomer is...
α-Alkylation of Ketones via Enolate Ions
Diels–Alder Reaction Forming Bridged Bicyclic Products: Stereochemistry
Diels–Alder Reaction: Characteristics of Dienophiles
Characteristics of Dienophiles
Generally, the best dienophiles are alkenes containing electron-withdrawing substituents such as carbonyl, nitrile, and nitro groups. The feasibility of a Diels–Alder reaction depends...
