Organocatalysed multicomponent synthesis of pyrazolidinones: Meldrum's acid approach

We discovered a novel organocatalysed multicomponent domino Knoevenagel-aza-Michael-cyclocondensation reaction leading to an unprecedented straightforward synthesis of 1,5-diazabicyclo[3.3.0]octane-2,6-diones. The specific capability of the (DHQ)(2)PHAL organocatalyst in this process was also highlighted to eventually furnish the corresponding bicyclopyrazolidinones with up to 96:4 er.