TY - JOUR
T1 - Two Directing Groups Used for Metal Catalysed Meta‐C–H Functionalisation Only Effect Ortho Electrophilic C–H Borylation
AU - Iqbal, Saqib A.
AU - Millet, Clement R. P.
AU - Pahl, Jürgen
AU - Yuan, Kang
AU - Ingleson, Michael
N1 - Funding Information:
This project has received funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme (grant agreement No 769599). We thank the Mass Spectrometry facility (SIRCAMS) at the University of Edinburgh for carrying out MS analysis. We thank Dr Lorna Murray from the NMR facility at the University of Edinburgh for assistance with variable temperature NMR spectroscopy. We also acknowledge Dr Gary Nichol from the X-ray crystallography department at the University of Edinburgh for collecting single crystal data.
Funding Information:
This project has received funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme (grant agreement No 769599). We thank the Mass Spectrometry facility (SIRCAMS) at the University of Edinburgh for carrying out MS analysis. We thank Dr Lorna Murray from the NMR facility at the University of Edinburgh for assistance with variable temperature NMR spectroscopy. We also acknowledge Dr Gary Nichol from the X‐ray crystallography department at the University of Edinburgh for collecting single crystal data.
Publisher Copyright:
© 2022 The Authors. European Journal of Organic Chemistry published by Wiley-VCH GmbH.
PY - 2022/10/21
Y1 - 2022/10/21
N2 - Two templates used in meta-directed C–H functionalisation under metal catalysis do not direct meta C–H borylation under electrophilic borylation conditions. Using BCl3 only Lewis adduct formation with Lewis basic sites in the template is observed. While combining BBr3 and the template containing an amide linker only led to amide directed ortho C–H borylation, with no pyridyl directed meta borylation. The amide directed borylation is selective for the ortho borylation of the aniline derived unit in the template, with no ortho borylation of the phenylacetyl ring – which would also form a six membered boracycle – observed. In the absence of other aromatics amide directed ortho borylation on to phenylacetyl rings can be achieved. The absence of meta-borylation using two templates indicates a higher barrier to pyridyl directed meta borylation relative to amide directed ortho borylation, and suggests that bespoke templates for enabling meta-directed electrophilic borylation may be required.
AB - Two templates used in meta-directed C–H functionalisation under metal catalysis do not direct meta C–H borylation under electrophilic borylation conditions. Using BCl3 only Lewis adduct formation with Lewis basic sites in the template is observed. While combining BBr3 and the template containing an amide linker only led to amide directed ortho C–H borylation, with no pyridyl directed meta borylation. The amide directed borylation is selective for the ortho borylation of the aniline derived unit in the template, with no ortho borylation of the phenylacetyl ring – which would also form a six membered boracycle – observed. In the absence of other aromatics amide directed ortho borylation on to phenylacetyl rings can be achieved. The absence of meta-borylation using two templates indicates a higher barrier to pyridyl directed meta borylation relative to amide directed ortho borylation, and suggests that bespoke templates for enabling meta-directed electrophilic borylation may be required.
U2 - 10.1002/ejoc.202200901
DO - 10.1002/ejoc.202200901
M3 - Article
SN - 1434-193X
VL - 2022
JO - European Journal of Organic Chemistry
JF - European Journal of Organic Chemistry
IS - 44
M1 - e202200901
ER -