The crude earthworm extract catalysed direct asymmetric Mannich reactionsa.

aOptimized reaction conditions: aldehyde (0.50 mmol), arylamine (0.55 mmol), cyclohexanone (5.00 mmol) or tetrahydrothiopyran-4-one (1.00 mmol), buffer (NaH2PO4-Na2HPO4, 0.20 M, pH = 7.53, 0.05 mL), isopropanol (0.95 mL), and the crude earthworm extract (50 mg) at 30°C.bYield of the isolated product after silica gel chromatography.cDetermined by chiral HPLC analysis performed using Chiralpak AD-H or Chiralcel OD-H column, by comparing the retention time with those of known compounds (For details, please see the Supplementary material).dThe chiral HPLC did not show baseline separation of peaks.eUn-optimized conditions: 4-nitrobenzaldehyde (0.50 mmol), aniline (0.55 mmol), cyclohexanone (5.00 mmol), deionized water (0.10 mL), isopropanol (0.90 mL) and the crude earthworm extract (50 mg) at 30°C.fThe reaction was carried out in the absence of the crude earthworm extract, otherwise under the same conditions as entry 7.