Asymmetric syntheses of enantiopure C(5)-substituted transpentacins via diastereoselective Ireland-Claisen rearrangements.

Asymmetric syntheses of (S,S,S)-2-amino-5-methylcyclopentanecarboxylic acid and (S,S,S)-2-amino-5-phenylcyclopentanecarboxylic acid were achieved in 9 steps from commercially available starting materials via the Ireland-Claisen rearrangement of two enantiopure β-amino allyl esters, followed by ring-closing metathesis, reduction and deprotection.