The Catalytic Regio- and Stereoselective Synthesis of 1,6-Diazabicyclo[4.3.0]nonane-2,7-diones

A straightforward synthesis of original 1,6-diazabicyclo[4.3.0]nonane-2,7-diones was achieved through a DBU-organocatalyzed multicomponent Knoevenagel-aza-Michael-Cyclocondensation reaction which takes advantage of an unprecedented highly regio- and diastereoselective conjugate addition of pyridazinones to alkylidene Meldrum's acid intermediates. The key reactive intermediates of this complex process were analyzed by means of electrospray ionization mass spectrometry coupled to ion mobility spectrometry, allowing us to validate the proposed mechanism.

Automated summary

A straightforward method for synthesizing original 1,6-diazabicyclo[4.3.0]nonane-2,7-diones was developed using a DBU-organocatalyzed multicomponent Knoevenagel-aza-Michael-Cyclocondensation reaction. Analysis of key reactive intermediates using mass spectrometry confirmed the proposed mechanism.