Metathesis Catalyst Ligand Design for Conjugated Diene Pheromone Synthesis
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Solution Overview
Problem
The high cost of insect pheromones limits their widespread use in controlling insect pests, and the preparation of conjugated diene pheromone compounds with controlled olefin geometry is particularly challenging, hindering their application in agricultural pest control.
Innovation Solution
A method involving the formation of a reaction mixture with an olefin, an aldehyde, and a metathesis catalyst comprising a transition metal and specific ligands, followed by a metathesis reaction and subsequent combination with a phosphonium ylide to produce conjugated dienes with high isomeric purity, enabling efficient synthesis of pheromone compounds like E,Z-dodecadien-7,9-1-yl acetate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional methods are used to prepare conjugated diene pheromones, then the synthesis process is complex and costly, but the product purity and olefin geometry control are insufficient
Solution Approach 1:
The patent employs metathesis catalysts with specific ligand combinations (N-heterocyclic carbene and phosphine ligands) to change the reaction parameters, achieving high olefin geometry control (E/Z selectivity) while simplifying the synthesis process. The catalyst system enables controlled formation of conjugated dienes with precise geometric configuration.
Solution Approach 2:
The metathesis catalyst acts as an intermediary that mediates the reaction between olefin and aldehyde components, facilitating the formation of conjugated diene pheromones with controlled geometry. The catalyst system includes transition metal centers coordinated with specific ligands that enable selective bond formation.
2Ease of manufacture
If pheromone production costs are reduced for widespread use, then accessibility improves, but maintaining high purity and selectivity becomes challenging
Solution Approach 1:
The patent uses readily available, inexpensive starting materials (olefins and aldehydes) that can be obtained from commercial sources or simple synthesis routes. The metathesis catalyst system enables efficient conversion of these simple materials into high-value pheromones, reducing overall production costs while maintaining product quality.
Solution Approach 2:
By optimizing reaction conditions including catalyst loading, temperature, and solvent selection, the method achieves high product purity and selectivity at scale. The use of mild reaction conditions and efficient catalyst systems reduces the need for complex purification steps, thereby lowering production costs while maintaining high manufacturing precision.
3Productivity
If industrial-scale production is implemented, then productivity increases, but controlling reaction selectivity and product quality becomes more difficult
Solution Approach 1:
The metathesis reaction system enables continuous processing at industrial scale while maintaining high selectivity. The catalyst system remains active and selective throughout the reaction, allowing for continuous production without compromising product quality. The reaction can be conducted in continuous flow or batch modes with consistent results.
Solution Approach 2:
The reaction system incorporates monitoring and control mechanisms to maintain optimal conditions during scale-up. By monitoring reaction progress and product composition, the process can be adjusted to maintain high selectivity and purity even at large production scales, ensuring consistent product quality.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method allows for the industrial-scale production of conjugated diene products with high selectivity and purity, reducing production costs and overcoming the challenges in synthesizing pheromones with controlled olefin geometry, thereby enhancing their potential for insect pest control.
Implementation Method 1
maintaining the reaction mixture under conditions sufficient to form a metathesis product
Implementation Method 2
combining the metathesis product according to Formula III with a phosphonium ylide according to Formula II under conditions sufficient to form the conjugated diene
Data Source
AI summary
Methods for preparing conjugated dienes are described. An α,β-unsaturated E olefin intermediate may be prepared via cross-metathesis using a catalyst comprising a transition metal (e.g., ruthenium), a first carbene ligand (e.g., a substituted indenylidene) and an N-heterocyclic carbene ligand (e.g., an imidazolidinylidene). The catalyst further includes a phenylphosphine ligand, a tri(isopropoxy)phosphine ligand, a dimethylsulfoxide ligand, an acetonitrile ligand, or a pyridine ligand. Following the cross metathesis-step, the α,β-unsaturated aldehyde intermediate may be converted to the conjugated diene product via reaction with a phosphonium ylide. Products obtained via the methods of the disclosure include (7E,9Z)-dodeca-7,9-dien-1-yl acetate, a pheromone produced by Lobesia botrana (European grapevine moth), and other insect pheromones.