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Preparation and Use of Carbonyl-decorated Carbenes in the Activation of White Phosphorus
Published on: October 3, 2014
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Azavinylidenephosphoranes: a class of cyclic push-pull carbenes
Florie Lavigne1, Aimée El Kazzi, Yannick Escudié
1Université de Toulouse, UPS, and CNRS, LHFA UMR 5069, 31062 Toulouse Cedex 9 (France), Fax: (+33) 561558204.
Chemistry (Weinheim an Der Bergstrasse, Germany)
|August 16, 2014
Summary
Researchers synthesized novel cyclic push-pull carbenes, specifically azavinylidene phosphoranes, using a [3+2] cycloaddition method. These carbenes display unique reactivity and strong σ-donating properties, making them excellent ligands for transition metals.
Area of Science:
- Organic Chemistry
- Organometallic Chemistry
- Catalysis
Background:
- Transient carbenes are highly reactive intermediates with diverse chemical applications.
- Push-pull carbenes, characterized by electron-donating and electron-withdrawing groups, exhibit unique electronic properties.
- Developing novel carbene structures with enhanced stability and coordination ability is crucial for catalysis.
Purpose of the Study:
- To synthesize and characterize a new family of cyclic push-pull carbenes, azavinylidene phosphoranes.
- To investigate the reactivity and electronic properties of these novel carbenes.
- To explore their potential as ligands in organometallic chemistry.
Main Methods:
- A formal [3+2] cycloaddition reaction between terminal alkynes and phosphine-imines.
- Subsequent oxidation and deprotonation steps to generate the target carbenes.
- Characterization using multinuclear NMR spectroscopy, X-ray crystallography, and Density Functional Theory (DFT) calculations.
Main Results:
- Successful synthesis of azavinylidene phosphoranes (carbenes 6) via the described methodology.
- Demonstration of typical transient carbene reactivity, including intramolecular C-H insertion.
- Exhibition of ambiphilic character through [2+1] cycloaddition with methyl acrylate.
- Formation of a stable Rh(I) complex (10) showcasing excellent coordination ability.
- Carbenes 6 identified as among the strongest σ-donating ligands, supported by DFT calculations.
Conclusions:
- Azavinylidene phosphoranes represent a novel class of cyclic push-pull carbenes.
- These carbenes possess tunable reactivity and strong σ-donating capabilities.
- Their coordination ability makes them promising ligands for transition metal catalysis.
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