Cispentacin - Enzymatic Highlights of its 25-Year History

Because of its natural occurrence and novel biological activity, interest in the investigation of (1R,2S)-2-aminocyclopentanecarboxylic acid (cispentacin) has rapidly increased. Since its activity against Candida albicans, C. neoformans, and a systemic C. infection, a number of enzymatic strategies for its preparation in enantiomerically pure form have been developed. Structural optimization of cispentacin resulted in the synthesis of derivatives such as (1R,2S)-2-amino-4-methylenecyclopentanecarboxylic acid with even superior efficacy in view of antifungal activity. Not only cispentacin itself and some of its small-molecule derivatives have been described as molecules of interesting bioactivity but it was also found that the cyclopentane β-amino acid moiety may be a key element of larger molecules with important pharmacological properties, such as the antibiotic amipurimycin. The present review is intended to give a brief insight into the most relevant enzymatic strategies for the synthesis of 25-year-old cispentacin and its close analogues containing the cispentacin subunit. These methods are classified as indirect or direct strategies. Some practical details for the preparative-scale resolution of a selected racemate furnishing cispentacin with excellent ee and very good yield are highlighted at the end of this overview.