The crude earthworm extract catalysed aza-Diels-Alder reactionsa.

aReaction conditions: aromatic aldehyde (0.50 mmol), aromatic amine (1.50 mmol), cyclohexenone (1.50 mmol), and the crude earthworm extract (100 mg) in MeCN (0.93 mL) and deionized water (0.07 mL) at 35°C for 96 h.bYield of the isolated products after silica gel chromatography.cCalculated according to the isolated weights of 15 and 16. The endo or exo was determined by 1HNMR in comparison with those of known compounds (For details, please see the Supplementary material).