Stereochemistry of LinB-catalyzed biotransformation of δ-HBCD to 1R,2R,5S,6R,9R,10S-pentabromocyclododecanol

► The bacterial dehalogenase LinB converts HBCDs like HCHs. ► Mono- and dihydroxylated products are formed during HBCD biotransformations. ► XRD-analysis revealed the solid-state structures of δ-HBCD and α2-PBCDOH. ► From these structures, the stereochemistry of the LinB-catalyzed transformation was elucidated. ► LinB induced a regio- and stereoselective, SN2-type substitution reaction.