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N-H Bond Activation of Ammonia Using Intramolecular cAAC-Borane Lewis Pairs
Hayoung Song1, Nathaniel K Szymczak1
1Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States.
Inorganic Chemistry
|August 25, 2025
Summary
We explored how a cyclic (alkyl)(amino)carbene-borane Lewis adduct reacts with water and ammonia. Ammonia triggers N-H bond activation and deprotonation, yielding a unique borane-stabilized lithium amide.
Area of Science:
- Organometallic Chemistry
- Boron Chemistry
- Carbene Chemistry
Background:
- Intramolecular cyclic (alkyl)(amino)carbene-borane Lewis adducts are novel compounds.
- Understanding their reactivity with small molecules is crucial for synthetic applications.
Purpose of the Study:
- To investigate the reaction of a specific carbene-borane adduct (1) with water and ammonia.
- To characterize the products and elucidate the reaction mechanisms.
Main Methods:
- Reaction of adduct (1) with water and ammonia under controlled conditions.
- Spectroscopic analysis (NMR, IR) and X-ray crystallography for product characterization.
Main Results:
- Water induced BBN ring expansion in adduct (1).
- Ammonia promoted N-H bond activation and subsequent deprotonation of the adduct.
- Isolation of a borane-stabilized lithium amide, a linear lithium complex.
Conclusions:
- The carbene-borane adduct exhibits distinct reactivity towards water and ammonia.
- Ammonia-mediated deprotonation offers a new route to borane-stabilized lithium amides.
- The linear lithium complex represents an uncommon structural motif.
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