G. Berti, F. Bottari, A. Marsili
1971
Citations
0
Influential Citations
10
Citations
Journal
Tetrahedron
Abstract
Abstract The treatment of A′-neogammacer-17(21)-ene oxide ( 1a ) with BF 3 ·Et 2 O complex in CHCl 3 produces entirely different results from those obtained when the same epoxide is treated with HCl in EtOH: while the protic acid converts the compound into the 15,17(21)-diene ( 2a ), the Lewis acid produces rearrangements in the carbon skeleton, with formation of the 28-nor-21α-methyl-12,17-diene ( 3a ) and of the 22,29,30-trisnor-17α-isopropyl-21-one ( 4a ). The structurally similar 19β,28-epoxy-A-neo-18α-olean-3(5)-ene oxide ( 1b ) behaves in a completely analogous manner.