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Enantioenriched Boron C,N-Chelates via Chirality Transfer
Yannick Stöckl1, Ethan J Tait1, Wolfgang Frey1
1Institut für Organische Chemie, Universität Stuttgart, Pfaffenwaldring 55, 70569, Stuttgart, Germany.
Chemistry (Weinheim an Der Bergstrasse, Germany)
|May 5, 2023
Summary
Synthesizing enantioenriched boron C,N-chelates is now feasible. This two-step method utilizes chiral aminoalcohols for stereochemical transfer, yielding valuable chiral boron compounds.
Area of Science:
- Organometallic Chemistry
- Stereoselective Synthesis
Background:
- Molecules with stereogenic centers at tetrahedral boron atoms are promising for applications like chiroptical materials.
- Their synthetic accessibility has been limited, hindering investigation.
Purpose of the Study:
- To develop a novel two-step synthesis for enantioenriched boron C,N-chelates.
- To enable efficient chirality transfer from readily available chiral auxiliaries to boron centers.
Main Methods:
- Diastereoselective complexation of borinates with chiral aminoalcohols to form stereogenic heterocycles.
- Chirality transfer via ate-complex intermediates using lithiated phenyl pyridine to yield C,N-chelates.
Main Results:
- Achieved up to 86% yield and >98:2 diastereomeric ratio (d.r.) in heterocycle formation.
- Successfully synthesized boron stereogenic C,N-chelates with up to 84% yield and 97:3 enantiomeric ratio (e.r.).
- Demonstrated tolerance for diverse boron substituents and successful post-modification while preserving stereochemistry.
Conclusions:
- A robust synthetic route to enantioenriched boron C,N-chelates has been established.
- The method allows for recovery of chiral ligands and further functionalization of the boron chelates.
- This work opens avenues for exploring boron-based chiral materials.
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