Amathaspiramides A–F

The amathaspiramides A–F are a class of marine alkaloids that have been isolated from a New Zealand collection of the bryozoan Amathia wilsoni by Prinsep and Morris. The core of these alkaloids is a highly functionalized aza-spirobicyclic structural framework possessing α-tert-alkylamino carbon center and a hemiaminal center. The amathaspiramides have exhibited excellent bioactivities as antiviral and antimicrobial agents, albeit with moderate cytotoxicity. This family of structurally complex natural products has attracted significant attention from the synthetic chemists. There are many different synthetic methodologies reported for total synthesis of different members of amathaspiramides A–F. Trauner and Ohfune completed the total synthesis of amathaspiramide F, whereas Fukuyama completed the total synthesis of A–F in a stereoselective way. The Tambar's group reported synthesis of amathaspiramide F, whereas Lee et al. completed total synthesis of amathaspiramide C; formal synthesis of A–F was reported via Fukuyama's route. Recently, Sun's group reported the synthesis of amathaspiramides B, D, and F in an asymmetric way.