Question

Taking with example write the mechanism of Mannich reaction?

Answer 1

CONVERSION OF $HCHO$

$HCHO+NHR_2\to O^{-}CH_2-N^{+}HR_2\to OH-CH_2-NR_2$

$OH-CH_2-NR_2+H^{+}\to CH_2=N^{+}R_2+H_2O$

$CH_2=N^{+}R_2\to C^{+}H_2-NR_2$

CONVERSION OF $R-CH_2-CRO$

$R-CH_2-CRO\to R-CH=CRO^{-}+H^{+}$

FINAL STEP

$R-CH=CRO^{-}+CH_2-N^{+}R_2\to NR_2-CH_2-CHR-CRO$