Honda Yukiko, Honda Tadashi, Roy Sujata, Gribble Gordon W
Department of Chemistry, Dartmouth College, 6128 Burke Laboratory, Hanover, NH 03755, USA.
J Org Chem. 2003 Jun 13;68(12):4991-3. doi: 10.1021/jo034056y.
It was previously reported that methyl oleanonate (5) and lanost-8-en-3-one (10) give predominantly [3,2-c]isoxazoles. On the contrary, we have confirmed that both compounds 5 and 10 do not give [3,2-c]isoxazoles but rather afford regioselectively [2,3-d]isoxazoles in good yields. Consequently, a new lanostane triterpenoid with a cyano-enone functionality in ring A was synthesized in two steps from the corresponding [2,3-d]isoxazole, which is interesting from the perspective of biological activity because lanosterol is the biogenetic precursor of steroids.
