Abstract
One of the most powerful approaches for the formation of simple and complex chiral molecules is the metal-catalysed asymmetric allylic alkylation. This reaction has been broadly studied with a great variety of substrates and nucleophiles under different reaction conditions and it has promoted the synthesis of new chiral ligands to be evaluated as asymmetric inductors. Although the mechanism as well as the active species equilibria are known, the performance of the catalytic system depends on the fine tuning of factors such as type of substrate, nucleophile nature, reaction medium, catalytic precursor and type of ligand used. Particularly interesting are chiral phosphines which have proved to be effective asymmetric inductors in several such reactions. The present review covers the application of phosphine-donor ligands in Pd-catalysed asymmetric allylic alkylation in the last decade.
Highlights
During the last decades, transition-metal catalysed reactions have played an important role in asymmetric organic synthesis by providing easy, selective, doable and environmentally friendly processes to produce a wide variety of organic products [1,2]
We provide an overview of the asymmetric allylic alkylation reaction with a main focus on phosphine ligands in combination with palladium precursors and stabilized nucleophiles for the enantioselective formation of C-C bonds covering the last decade
Mahadik reported the use of (1R,2S)-norephedrine and (1S,2S)-seudonorephedrine as chiral scaffold for the construction of ligands L23a and L23b (Figure 9) [69]. These compounds were employed in the asymmetric allylic alkylation reaction shown in Equation (1), Scheme 2
Summary
Transition-metal catalysed reactions have played an important role in asymmetric organic synthesis by providing easy, selective, doable and environmentally friendly processes to produce a wide variety of organic products [1,2]. Differing from cross-coupling reactions, AAA generates stereogenic centres by controlling the attack of the nucleophile to a metal-coordinated allylic substrate. When racemic or prochiral substrates with identical substituents at the terminal allylic carbons are employed (rac-1, Scheme 2), the enantioselectivity depends on the regioselectivity of the nucleophilic attack. Trost alkylation conditions (i.e. N,O-bis(trimethylsilyl)acetamide (BSA), KOAc in catalytic amount and [Pd( 3-C3H5)Cl]2) are considered as default conditions unless otherwise stated Other reaction conditions such as temperature, nature of the palladium precursor, or substrate and nucleophile will be defined in the text when necessary. We provide an overview of the asymmetric allylic alkylation reaction with a main focus on phosphine ligands in combination with palladium precursors and stabilized nucleophiles for the enantioselective formation of C-C bonds covering the last decade
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
