Rhodium-Carbynoids Turn Alkenes into Allylic Building Blocks

  • Author: ChemistryViews.org
  • Published: 30 September 2019
  • Copyright: Wiley-VCH Verlag GmbH & Co. KGaA
  • Source / Publisher: Journal of the American Chemical Society/ACS Publications
  • Associated Societies: American Chemical Society (ACS), USA
thumbnail image: Rhodium-Carbynoids Turn Alkenes into Allylic Building Blocks

Metal carbyne complexes, i.e., species with a metal–carbon triple bond (M≡CR), are common in alkyne metathesis. However, their general use for carbyne transfer has not been well explored. This is due to a lack of carbyne souces. This problem could be solved by using metal-carbynoids as equivalents instead of metal-carbynes. A metal–carbene complex with a good leaving group, for example, could act as such an equivalent.


Marcos G. Suero, Institute of Chemical Research of Catalonia (ICIQ), Tarragona, Spain, have found that rhodium-carbynoids can be synthesized from a carbyne precursor with a hypervalent iodine moiety, a diazo group, and a CO2Et group. These carbyne sources were subjected to a selective diazo activation in the presence of paddlewheel dirhodium complexes of the type L4Rh2 (L = acetate, trifluoroacetate, heptafluorobutyrate, etc.). Due to the outstanding leaving group ability of the hypervalent iodine unit, the resulting rhodium-carbynoids act like a monovalent cationic carbyne.


The Rh-carbynoids can be used as a catalyst to insert a single carbon into the middle of the C(sp2)–C(sp2) bond of an alkene (pictured top). The resulting allylic cation can react with a nucleophile to give substituted allyl species (pictured bottom). According to the researchers, the insertion reaction proceeds via a hypervalent-iodine-substituted cyclopropyl intermediate. The reaction can be used to extend the carbon skeleton of organic compounds and build complex structures.


 

Article Views: 575

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

Bookmark and Share

If you would like to reuse any content, in print or online, from ChemistryViews.org, please contact us first for permission. more


CONNECT:

ChemistryViews.org on Facebook

ChemistryViews.org on Twitter ChemistryViews.org on YouTube ChemistryViews.org on LinkedIn Sign up for our free newsletter


A product of ChemPubSoc Europe (16 European Chemical Societies)and Wiley-VCH