Cu-Catalyzed Asymmetric Hydroboration of Chromenes
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Solution Overview
Problem
Current methods for synthesizing flavan-3-ols are inefficient, with limited strategies for achieving high enantioselectivity and scalability, particularly in the construction of flavan-3-ol skeletons and their use in treating inflammatory diseases.
Innovation Solution
A novel Cu-catalyzed asymmetric hydroboration process for kinetic resolution of chromenes, resulting in highly efficient synthesis of chiral flavan-3-ols with up to 99% enantiomeric excess and trans product selectivity, which are then shown to inhibit pro-inflammatory cytokine secretion and inflammation pathways.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional multi-step synthesis methods are used to construct chiral flavan-3-ols, then the synthesis can be performed with established protocols, but the process requires multiple steps, uses complex catalysts, and results in lower productivity
Solution Approach 1:
The synthesis is divided into two independent stages: (1) asymmetric hydroboration of chromenes to generate chiral organoboron intermediates with high enantioselectivity, and (2) oxidation of the boron intermediates to produce flavan-3-ols. This segmentation allows each step to be optimized independently, achieving both high enantioselectivity (>99% ee) and improved productivity through streamlined methodology.
Solution Approach 2:
Chiral organoboron compounds are used as versatile intermediates that can be easily transformed into chiral flavan-3-ols through oxidation. The C-B bond serves as a strategic intermediary that enables stereospecific transformation into C-O, C-C, C-N, and C-halogen bonds, facilitating efficient construction of the flavan-3-ol framework with high enantioselectivity.
2Manufacturing precision
If kinetic resolution is applied to achieve high enantiomeric excess, then the enantioselectivity improves significantly, but the scope of suitable substrates and catalysts remains limited
Solution Approach 1:
The Cu-catalyzed asymmetric hydroboration system developed in this patent exhibits universal applicability across a broad scope of chromene substrates. The methodology successfully resolves various 2-substituted chromenes, including flavanones and dihydroquinolines, delivering chiral products with high enantiomeric excess (>99% ee) and excellent diastereoselectivity, thereby overcoming the limitation of narrow substrate scope.
Solution Approach 2:
The patent employs parameter optimization including catalyst loading (5 mol%), temperature control (-78°C to 0°C), and solvent selection (CH2Cl2, THF, MeOH) to achieve high enantioselectivity across diverse substrates. These parameter adjustments enable the kinetic resolution to be applied universally to different chromene derivatives while maintaining >99% enantiomeric excess.
3Ease of manufacture
If natural flavan-3-ols are isolated from plants, then the compounds can be obtained in natural forms, but the isolation process is tedious and difficult to achieve in pure form
Solution Approach 1:
The patent replaces the mechanical/isolation-based approach with a chemical synthesis approach using Cu-catalyzed asymmetric hydroboration followed by oxidation. This substitution transforms the tedious isolation process into a streamlined synthetic route that directly produces pure chiral flavan-3-ols with >99% enantiomeric excess, eliminating the need for complex natural product isolation procedures.
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 synthesized flavan-3-ols demonstrate potent anti-inflammatory effects by inhibiting IL-1β, IL-6, and TNF-α secretion and downregulating related gene transcriptions, indicating their potential as lead compounds for inflammatory disease treatment.
Implementation Method 1
A highly efficient kinetic resolution of chromenes for the first time via Cu-catalyzed asymmetric hydroboration
Implementation Method 2
Cu-catalyzed asymmetric hydroboration of alkenes has proven to be a direct and powerful method for the preparation of chiral alkylboronic acid derivatives
Implementation Method 3
The compounds exhibit inhibitory effects on the expression and secretion of pro-inflammation cytokines, such as IL-1β, IL-6 and TNF-α
Implementation Method 4
inhibiting the inflammation responses through downregulating the gene transcriptions closely related to IL-17 signaling pathway, PI3K-Akt signaling pathway and TNF signaling pathway
Data Source
AI summary
Provided herein are compounds useful in the treatment of inflammatory diseases, pharmaceutical compositions comprising the same, and methods of use and preparation thereof. The compounds exhibit inhibitory effects on the expression and secretion of pro-inflammatory cytokines, such as IL-1β, IL-6 and TNF-α.