Solid Organozinc Reagents via Zinc Coordination Complexes
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Solution Overview
Problem
Organozinc reagents used in Negishi-coupling reactions are typically obtained as highly viscous oils, making them unsuitable for industrial-scale storage and handling as solids, and there is a need to increase the selectivity of cross-coupling reactions to accommodate sensitive functional groups like esters, aldehydes, nitriles, and nitro groups.
Innovation Solution
A process involving zinc coordination complexes and organomagnesium complexes is developed to produce solid organozinc reagents, allowing for the formation of organic compounds through cross-coupling or aldehyde/ketone addition reactions, enabling the use of sensitive functional groups and facilitating the storage and handling of these reagents as solids.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If organozinc reagents are prepared by direct oxidative addition of zinc metal into organic halides, then the reagents can be obtained in good yields with broad spectrum of electrophiles, but the reagents are obtained as highly viscous oils that are unsuitable for industrial-scale storage and handling
Solution Approach 1:
The patent introduces zinc coordination complexes as intermediary substances that mediate between the organozinc reagent and storage conditions. These complexes act as a bridge, allowing the reagent to be stabilized in a solid form while maintaining its chemical identity and reactivity when needed.
Solution Approach 2:
The patent changes the physical state parameter of the organozinc reagent from liquid (viscous oil) to solid by introducing zinc coordination complexes. This parameter change enables the reagent to be stored and handled as a solid material while preserving its chemical functionality.
2Productivity
If conventional cross-coupling reactions are performed, then good yields are achieved, but sensitive functional groups such as ester, aldehyde, nitrile and nitro groups cannot be present in the electrophiles due to lack of selectivity
Solution Approach 1:
The patent applies local quality by making the zinc reagent selectively reactive at specific sites while leaving sensitive functional groups unaffected. The zinc coordination complex provides localized reactivity control, allowing the reaction to occur only where needed while preserving other functional groups in the molecule.
Solution Approach 2:
The patent changes the reactivity parameter of the cross-coupling reaction by introducing zinc coordination complexes, which modify the reaction conditions to be milder and more selective. This parameter change enables the reaction to proceed with sensitive functional groups present without compromising yield or selectivity.
3Reliability
If organozinc reagents are stored as solutions in THF under inert gas atmosphere, then they can be stored for several weeks without significant loss of activity, but this requires specialized storage conditions and is not suitable for industrial-scale operations
Solution Approach 1:
The patent extracts the solvent (THF) from the organozinc reagent solution by introducing zinc coordination complexes that enable the reagent to exist in a solid state. This extraction eliminates the need for solvent-based storage systems and inert gas atmospheres, simplifying the storage infrastructure.
Solution Approach 2:
The patent utilizes a phase transition from liquid solution to solid material by introducing zinc coordination complexes. This phase transition allows the reagent to be stored as a stable solid that does not require specialized storage conditions, thereby reducing device complexity while maintaining reliability.
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
The process allows for the production of solid organozinc reagents that can be stored and handled more efficiently, while enabling cross-coupling reactions with a broad range of electrophiles, including those with sensitive functional groups, under mild conditions, improving yield and selectivity.
Implementation Method 1
A process involving zinc coordination complexes and organomagnesium complexes is developed to produce solid organozinc reagents
Implementation Method 2
The coordination complex comprises at least one zinc ion and at least one coordinating compound
Data Source
AI summary
Processes for making an organozinc reagents are disclosed comprising reacting (A) organomagnesium or organozinc complexes with (B) at least one coordination compound comprising one or more carboxylate groups and/or alcoholate groups and/or tertiary amine groups, optionally in combination with zinc ions and/or lithium ions and/or halide ions, wherein the halide ions are selected from chloride, bromide and iodide, the organozinc complex comprises an aryl group, a heteroaryl group or a benzyl group when the coordinating compound is a chelating polyamine, and the reaction is conducted in the presence of zinc complexed with at least one coordinating compound when reactant (A) comprises at least one organomagnesium complex. The resulting organozinc reagents may optionally be isolated from solvents to obtain a solid reagent. The reagents may be used for making organic compounds via Negishi cross-coupling reactions or via aldehyde and/or ketone oxidative addition reactions. The organozinc reagents are stable and, due to their high selectivity, permit maintenance of sensitive functional groups such as aldehydes during cross-coupling.