The compounds you smell in your pee after eating asparagus are most likely thioethers (although the literature over the last one hundred years on this subject includes some debate—no joke). That’s a sulfur atom with two carbon substituents. Asparagus, for some reason, has high levels of sulfur-containing amino acids. Your body breaks these down into chemicals that smell like rotten eggs or other foul odors.
Asparagus has a lot of sulfur-containing amino acids, and when you urinate after eating this vegetable, the sulfur can be smelled in your waste.