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A new class of stable four-coordinated benzotriazole-borane compounds was developed via gold-catalyzed alkyne hydroboration. The application of polymeric (BH 2 CN) n reagent gave the formation of cyano-amine-boranes (CAB) complexes with less basic N-heterocyclic amines and anilines. Various new CABs were investigated in catalytic hydroboration to synthesize N–B cycles. The 1,2,3-benzotriazoles were identified as the only feasible N-source, giving the four coordinated borane N–B cycles (BTAB) in excellent yields (up to 90%) with good functional group tolerability. This new class of polycyclic N–B compounds showed excellent stability toward acid, base, high temperature, and photo-irradiation. The facile synthesis, excellent stability, strong and tunable fluorescence emission make BTAB interesting new fluorescent probes for future chemical and biological applications.
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Highly efficient and selective hydroboration of terminal and internal alkynes catalysed by a cobalt( ii ) coordination polymer
Hydroboration of terminal and internal alkynes has been carried out with extremely high efficiency by using a bench-stable and inexpensive cobalt( ii ) coordination polymer as a precatalyst in the presence of potassium tert -butoxide (KO t Bu). Good to high yields of alkenylboronate esters were obtained in 5–30 min with low catalyst loading (0.025 mol%). Good chemoselectivity for alkyne vs alkene hydroboration was observed. A possible catalytic cycle involving the in situ formation of an active Co–H species is proposed based on additional experimental results. This work provides valuable implications for the design of efficient and practical base metal catalysts.
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- Award ID(s):
- 1900500
- PAR ID:
- 10155567
- Date Published:
- Journal Name:
- Organic Chemistry Frontiers
- Volume:
- 6
- Issue:
- 18
- ISSN:
- 2052-4129
- Page Range / eLocation ID:
- 3228 to 3233
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Giant N-heterocyclic carbene-containing organic macrocycles larger than “Texas-sized” molecular boxes have been synthesized and structurally characterized. The new macrocycles were employed for the Co-NHC promoted syn -selective hydroboration of alkynes with good stereo- and regioselectivity.more » « less
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1039/C9QO00834A
