(S)-3-Hexyl-5,6-dihydro-6-undecyl-2H-pyran-2-one

(S)-3-Hexyl-5,6-dihydro-6-undecyl-2H-pyran-2-one is a chiral cyclic ester derivative featuring a substituted dihydropyran-2-one core, with an (S)-configured hexyl side chain at C3 and a linear undecyl group at C6. The molecule exhibits a fused cyclohexane-like ring system with a terminal ketone functionality, analogous to Orlistat's pharmacophore but lacking the terminal ester. Its stereochemistry and alkyl substitution pattern correspond to a key synthetic intermediate or degradation byproduct formed during Orlistat production via ring-closing metathesis pathways. This compound serves as an HPLC reference standard for quantifying process-related impurities in Orlistat APIs.