Related Experiment Video
Updated: May 21, 2025

Preparation of Stable Bicyclic Aziridinium Ions and Their Ring-Opening for the Synthesis of Azaheterocycles
Published on: August 22, 2018
CO and CS bond activation by an annulated 1,4,2-diazaborole
Vignesh Pattathil1, Conor Pranckevicius1
1Department of Chemistry, Charles E. Fipke Centre for Innovative Research, University of British Columbia, Okanagan Campus, 3247 University Way, Kelowna, BC, Canada. conor.pranckevicius@ubc.ca.
Abstract:
The reaction of an ambiphilic 1,4,2-diazaborole with CO and CS bonds results in formal (3 + 2) cycloaddition and has allowed the synthesis of a family of 1,3,2-oxazaborole and 1,3,2-thiazaborole derivatives. Computational calculations have indicated a dipolar mechanism where the π bond is concertedly activated via the Lewis acidic boron centre and the nucleophilic C5 position of the 1,4,2-diazaborole. In the case of methylisothiocyanate, preference for CS over CN addition is observed, and has been rationalized according to mechanistic calculations. A spirocyclic bis(1,3,2-thiazaborole) has been observed from the double activation of CS2.
Related Concept Videos
Cycloaddition Reactions: MO Requirements for Thermal Activation
ortho–para-Directing Activators: –CH3, –OH, –⁠NH2, –OCH3
[3,3] Sigmatropic Rearrangement of 1,5-Dienes: Cope Rearrangement
Cycloaddition Reactions: MO Requirements for Photochemical Activation
Aryldiazonium Salts to Azo Dyes: Diazo Coupling
[4+2] Cycloaddition of Conjugated Dienes: Diels–Alder Reaction

