Epoxidation of alnus-5-en-3β-yl acetate with m-chloroperbenzoic acid gave a 5β,6β-epoxide as a main product together with a 5α,6α-epoxide as a minor product. Treatment of the α-epoxide with BF3·OEt2 afforded a 1(10),5-diene and a mixture of 6α-hydroxy-12- and -18-ene derivatives. The 12-ene was converted into daturadiol (=olean-12-ene-3β,6β-diol).
Contrary to the reported literature, the main epoxide derived from alnus-5-en-3β-yl acetate (1) was shown to be a β-epoxide. Daturadiol (=olean-12-ene-3β,6β-diol) was prepared from dendropanoxide via 1 and its α-epoxide.