Regioselective Amine–Borane Cyclization: Towards the Synthesis of 1,2‐BN‐3‐Cyclohexene by Copper‐Assisted Triazole/Gold Catalysis |
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| Authors: | Stephen E Motika Dr Qiaoyi Wang Dr Novruz G Akhmedov Dr Lukasz Wojtas Prof Dr Xiaodong Shi |
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| Affiliation: | 1. Department of Chemistry, University of South Florida, Tampa, FL, USA;2. Department of Chemistry, West Virginia University, Morgantown, WV, USA |
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| Abstract: | The combination of triazole/gold (TA‐Au) and Cu(OTf)2 is identified as the optimal catalytic system for promoting intramolecular hydroboration for the synthesis of a six‐membered cyclic amine–borane. Excellent yields (up to 95 %) and regioselectivities (5‐exo vs. 6‐endo) were achieved through catalyst control and sequential dilution. Good functional‐group tolerance was attained, thus allowing the preparation of highly functionalized cyclic amine–borane substrates, which could not be achieved using other methods. Deuterium‐labeling studies support the involvement of a hydride addition to a gold‐activated alkyne with subsequent C?B bond formation. |
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| Keywords: | boranes copper heterocycles gold reaction mechanisms |
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