Carboxy-MIDA-Boronate Stabilizes Boron for Cross-Coupling
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Solution Overview
Problem
The limited synthetic utility of borylcarboxylic acids and their derivatives due to difficulties in preparation and subsequent transformations, particularly in engaging the C—B bond in classical cross-coupling reactions, restricts their application in chemical synthesis.
Innovation Solution
The development of carboxy-N-methyliminodiacetic acid (MIDA)-boronate, which shields boron's empty p orbital, enabling transformations mediated by boronic acids such as Suzuki-Miyaura cross-coupling reactions, and the synthesis of borylated products through scalable and operationally straightforward methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If trivalent organoboron compounds are used, then reactivity is improved due to accessible vacant p-orbital, but stability deteriorates as they are too reactive to survive chemical transformations
Solution Approach 1:
The patent introduces tetracoordinate organoboronic derivatives (such as organotrifluoroborates and MIDA boronates) as intermediary compounds that mediate between the reactive trivalent boron species and the desired transformation. These tetracoordinate compounds stabilize the boron center through additional bonding while preserving reactivity for specific transformations, thus resolving the contradiction between stability and reactivity.
Solution Approach 2:
The patent changes the coordination number of boron from three to four, fundamentally altering the electronic and steric parameters of the boron center. This parameter change transforms the highly reactive trivalent boron into more stable tetracoordinate boron, while still maintaining accessibility for controlled chemical transformations through the preserved vacant p-orbital character.
2Ease of manufacture
If borylcarboxylic acids and their derivatives are prepared, then access to borylated compounds is improved, but synthetic utility deteriorates due to difficulties in preparing and engaging C-B bond in cross-coupling reactions
Solution Approach 1:
The patent employs tetracoordinate organoboronic derivatives as intermediary compounds that facilitate the engagement of C-B bonds in cross-coupling reactions. These intermediaries stabilize the boron center while maintaining reactivity toward palladium catalysts, thereby enabling successful Suzuki-Miyaura cross-coupling transformations that were previously difficult to achieve with borylcarboxylic acids.
Solution Approach 2:
The patent modifies the chemical parameters of boron-containing compounds by transitioning from trivalent to tetracoordinate boron species. This parameter change enhances the stability and versatility of the C-B bond for cross-coupling reactions while maintaining ease of preparation, thus resolving the contradiction between manufacturability and synthetic utility.
3Reliability
If sp2-hybridized boron species are used, then Lewis acidity is improved, but stability deteriorates as they are too reactive to survive chemical transformations
Solution Approach 1:
The patent changes the hybridization and coordination number of boron from sp2 trivalent to sp3 tetracoordinate. This parameter change modifies the electronic structure to maintain Lewis acidity through the vacant p-orbital while simultaneously improving stability through the tetrahedral geometry and reduced reactivity, thus resolving the contradiction between reliability and stability.
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 carboxy-MIDA-boronate allows for stable and versatile access to borylated amides, esters, and heterocyclic scaffolds, demonstrating enhanced synthetic utility and capability in complex molecule synthesis and pharmaceutical applications.
Implementation Method 1
The development of carboxy-N-methyliminodiacetic acid (MIDA)-boronate, which shields boron's empty p orbital
Implementation Method 2
oxidizing the compound of Formulas (2)
Data Source
AI summary
There is provide herein a compound of Formula (3):wherein R1, R2, R3, R4, R5, R6, and R7 are each independently H or an organic group.