A De Novo Stereocontrolled Approach to syn ‐ and anti ‐Disubstituted Acyclic β 2,3 ‐Amino Acid Enantiomers

The stereocontrolled syntheses of functionalized acyclic β 2,3 ‐amino acid derivatives in enantiomerically pure form were performed by starting from enantiopure cis‐ and trans ‐2‐aminocyclopent‐3‐enecarboxylates, which were derived from a racemic bicyclic β‐lactam. The synthetic strategy involves the stereoselective dihydroxylaton of the C–C double bond of the cyclopentene β‐amino esters. The subsequent NaIO 4 ‐mediated ring cleavage affords dialdehyde intermediates that undergo functionalization by a Wittig reaction.