Total synthesis of dl-anisomycin.

Epoxidation of 2-(p-methoxyphenylmethyl)-1-benzyloxycarbonyl-3-pyrroline (39) with pertrifluoroacetic acid gave 3α, 4α-epoxide (40) and 3β, 4β-epoxide (41). Acetolysis of 41 predominantly yielded 4α-acetoxy-3β-hydroxypyrrolidine (43), which was converted into the α-epoxide (40) by mesylation and successive treatment with bases. Treatment of the α-epoxide (40) with trifluoroacetic acid, followed by acetylation and removal of the protecting groups gave 4α-acetoxy-3β-hydroxypyrrolidine (47) and dl-anisomycin (1). 1 showed superimposed infrared and nuclear magnetic resonance spectra with those of natural anisomycin and exhibited one-half the activity against Candida albicans. In addition, the epoxide-cleavage reaction of these 3, 4-epoxypyrrolidines was discussed.