5 years ago

Synthesis and Reduction of Sterically Encumbered Mesoionic Carbene-Stabilized Aryldihaloboranes

Synthesis and Reduction of Sterically Encumbered Mesoionic Carbene-Stabilized Aryldihaloboranes
Haopeng Gao, Holger Braunschweig, Merle Arrowsmith, Jens Seufert, Marc-André Légaré, Valerie Paprocki, Julian Böhnke
Sterically hindered, in situ generated 1,3,4-substituted 1,2,3-triazol-5-ylidene mesoionic carbenes (MICs) were employed to stabilize a number of aryl- and heteroaryldihaloboranes, as well as the first MIC-supported diborane. Reduction of borane adducts of the 1-(2,6-diisopropylphenyl)-3-methyl-4-tert-butyl-1,2,3-triazol-5-ylidene ligand with KC8 in non-coordinating solvents led to intramolecular C−H- and, C−C-activation at an isopropyl residue of the supporting ligand. DFT calculations showed that each of these activation reactions proceeds via a different isomer of a borylene intermediate. Sterically encumbered mesoionic carbene adducts of (hetero)aryldihaloboranes and a diaryldihalodiborane were obtained by borane addition to in situ deprotonated 1,3,4-substituted 1,2,3-triazoles. Reduction with KC8 in toluene led to competitive intramolecular C−H and C−C activation at a ligand isopropyl group via two distinct borylene pathways, as determined by computational modelling.

Publisher URL: http://onlinelibrary.wiley.com/resolve/doi

DOI: 10.1002/chem.201700500

You might also like
Discover & Discuss Important Research

Keeping up-to-date with research can feel impossible, with papers being published faster than you'll ever be able to read them. That's where Researcher comes in: we're simplifying discovery and making important discussions happen. With over 19,000 sources, including peer-reviewed journals, preprints, blogs, universities, podcasts and Live events across 10 research areas, you'll never miss what's important to you. It's like social media, but better. Oh, and we should mention - it's free.

  • Download from Google Play
  • Download from App Store
  • Download from AppInChina

Researcher displays publicly available abstracts and doesn’t host any full article content. If the content is open access, we will direct clicks from the abstracts to the publisher website and display the PDF copy on our platform. Clicks to view the full text will be directed to the publisher website, where only users with subscriptions or access through their institution are able to view the full article.