Stereochemistry of hydrogen removal from the 'unactivated' C-30 position of 4-hydroxybutyryl-CoA catalysed by 4-hydroxybutyryl-CoA dehydratase

(R)- and (S)-gamma-[3-H-2(1)]butyrolactones have been synthesised from (R)- and (S)-glycidol, respectively, and used to demonstrate that it is the pro-(S) hydrogen atom that is stereospecifically abstracted from C-3 of 4-hydroxybutyryl-CoA by 4-hydroxybutyryl-CoA dehydratase, and that this atom is not returned to C-4.