Tandem Cycloaddition Using o-Carborynes Gives Tricyclics

  • Author: ChemistryViews.org
  • Published: 21 March 2021
  • Copyright: Wiley-VCH GmbH
  • Associated Societies: Royal Society of Chemistry (RSC), UK
thumbnail image: Tandem Cycloaddition Using <i>o</i>-Carborynes Gives Tricyclics

Carboranes are clusters composed of boron, carbon, and hydrogen atoms. In ortho- or o-carboranes, two neighboring vertices of the cluster cage are Cā€“H units. These clusters can be considered three-dimensional versions of benzene derivatives. Just like benzene can be converted to the reactive benzyne by formally removing two hydrogen atoms, the ortho-carborane o-C2B10H12 can be converted to 1,2-dehydro-o-carborane, or o-carboryne.


Jie Zhang and Zuowei Xie, The Chinese University of Hong Kong, China, have used o-carboryne for [4+2] cycloadditions with conjugated enynes, followed by a [2+2] cycloaddition to give carborane-fused tricyclic compounds (pictured, tricyclo[6.4.0.02,7]dodeca-2,12-dienes). The team used 1-Li-2-OTf-o-C2B10H10 as a carboryne precursor, which was prepared in situ from 1-OTf-o-C2B10H11 and lithium bis(trimethylsilyl)amide (LiHMDS). This was directly followed by a tandem cycloaddition reaction with conjugated enynes, which was performed in cyclohexane at room temperature.


The desired carborane-fused tricyclic compounds were obtained in moderate to good yields. According to the researchers, the reaction first generates a reactive carborane-fused 1,2-cyclohexadiene intermediate, which then undergoes a [2+2] cycloaddition to form the central four-membered ring.


 

 

Article Views: 6084

Sign in Area

Please sign in below

Additional Sign In options

Please note that to comment on an article you must be registered and logged in.
Registration is for free, you may already be registered to receive, e.g., the newsletter. When you register on this website, please ensure you view our terms and conditions. All comments are subject to moderation.

Article Comments - To add a comment please sign in

If you would like to reuse any content, in print or online, from ChemistryViews.org, please contact us first for permission and consult our permission guidance prior to making your request

Follow on Facebook Follow on Twitter Follow on YouTube Follow on LinkedIn Follow on Instagram RSS Sign up for newsletters

Magazine of Chemistry Europe (16 European Chemical Societies) published by Wiley-VCH