Regioselective inverse Diels-Alder reaction of unsymmetrical tetrazines with aldehydes and ketones

The amine-catalyzed inverse electron demand Diels-Alder reaction of unsymmetrical tetrazines with aldehydes and ketones was investigated.We found that only one regioisomer could be observed when pyrrolidine was applied as the catalyst.Using this reaction, fluorogenic dyes could be developed with a tetrazine unit as the "triggering group".