Masked Oxygen-Substituted Isocyanates

  • Author: Li Grundl
  • Published: 26 October 2017
  • Copyright: Wiley-VCH Verlag GmbH & Co. KGaA
  • Source / Publisher: Advanced Synthesis & Catalysis/Wiley-VCH
thumbnail image: Masked Oxygen-Substituted Isocyanates

Isocyanates are important reagents in synthetic organic chemistry and have a wide range of applications. While carbon-substituted isocyanates are common, oxygen-substituted isocyanates (pictured) are rare because they are highly reactive and prone to Lossen rearrangements or homotrimerization. However, O-substituted isocyanates could be versatile reagents in the synthesis of bioactive compounds, if their reactivity can be controlled and unwanted reactions can be prevented.

André M. Beauchemin, University of Ottawa, Canada, and colleagues have developed a controlled cascade reaction to synthesize hydantoins and dihydrouracils, using masked O-isocyanates and amino esters as starting materials. The reactions are carried out in MeCN or THF at 70–120 °C. They use i-Pr2NEt or DBU (1,8-diazabicyclo[5.4.0]undec-7-ene) as the base and give the products in good yields.

The researchers have studied the influence of the blocking group on the reactivity and found that phenol is the best one for the cascade reaction because the desired O-isocyanates are conveniently released in situ from the crystalline precursors without causing side reactions. The developed method is the first cascade reaction using O-isocyanates as reactive intermediates.


Article Views: 962

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, please contact us first for permission. more

CONNECT: on Facebook on Twitter on YouTube on LinkedIn Sign up for our free newsletter

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