Research has shown that chiral sulfide organocatalysts can catalyze asymmetric reactions to produce products with high stereoselectivity. Other studies suggest that chiral selenium organocatalysts have similar abilities. We are interested in comparing their catalytic abilities. This research focuses on the synthesis of chiral selenium organocatalysts THSeOBn and testing its properties in catalyzing the formation of aziridines and epoxides asymmetrically. Our findings show that, compared to the chiral sulfide organocatalysts THTOBn, THSeOBn significantly improves both the diastereomeric ratio(dr) and reaction rate in aziridination. However, the reaction rate of epoxidation also increases, the dr value decreases. Lastly, we suggest a possible reaction mechanism for aziridination and epoxidation using THSeOBn as a chiral selenium organocatalyst.