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 beta-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.