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Published on: February 16, 2020
Alkyne Dihydroboration via In Situ-Formed Nickel Cluster Catalysis: Reordering Group Addition by Multinuclear Nature
Yuyang Su1, Kaidong Shen2, Pingsen Shi3
1State Key Laboratory of Organometallic Chemistry and Shanghai Hongkong Joint Laboratory in Chemical Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, P. R. China.
This study introduces a nickel-catalyzed system for the double hydroboration of alkynes using in situ-formed nanoclusters. It efficiently synthesizes sterically hindered compounds via a novel gem-addition mechanism.
Area of Science:
- Catalysis
- Nanomaterials Chemistry
- Organic Synthesis
Background:
- Understanding in situ-formed nanoclusters in catalysis is challenging.
- Multimetallic nanoclusters exhibit unique catalytic mechanisms distinct from molecular or heterogeneous catalysts.
Purpose of the Study:
- To develop a catalytic system for regioselective double hydroboration of unsymmetrical internal alkynes.
- To explore the catalytic activity of in situ-generated nickel nanoclusters.
Main Methods:
- Nickel-catalyzed reaction of internal alkynes with pinacolborane (HBpin).
- Mechanistic studies to elucidate the catalytic pathway.
Main Results:
- Efficient synthesis of sterically congested quaternary 1,1-diboryl alkanes.
- Demonstration of simultaneous activation of multiple HBpin molecules by Ni nanoclusters.
- Evidence for a novel gem-addition mechanism (geminal H, H and B, B addition).
Conclusions:
- In situ-generated Ni nanoclusters enable unprecedented reactivity in double hydroboration.
- The discovered gem-addition pathway differs fundamentally from sequential hydroboration.
- Polynuclear nanocluster architectures offer advantages for novel catalytic pathways.
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