Total Synthesis of (+)-Fawcettimine

摘要

The fawcettimine class of Lycopodium alkaloids consists of over 60 natural products. Typically, these tetracyclic compounds contain a single quaternary carbon center and are derived biosynthetically from the lycopodane core through an oxidative rearrangement reaction. In 1959, the first member of this class, fawcettimine (1), was isolated by Burnell in the Blue Mountain Range of Jamaica.'21 Inubushi and co-workers later confirmed the structure by chemical correlation through X-ray crystallography.'31 Heathcock and co-workers subse-quently demonstrated that the carbinolamine 1 was in equilibrium with the corresponding ketone and therefore underwent facile epimerization at C-4. Since the discovery of fawcettimine, a number of related compounds have also been isolated. For example, the C4-functionalized derivatives lycoflexin (2) and alopecuridine (3) were reported in 1973 and 1974, respectively. More recently, lycoposerramine-A(4) with a 1,2,4-oxadiazolidin-5-one structure and lycoposerr-amine-B (5) with a mono oxime functionality were discovered and proposed to be biosynthetically derived from fawcettimine (1).