Compound 18 was converted into 27, which on ozonolysis gave ketone 31. The latter was treated with Ca in liquid NH3 to afford 3. The work constitutes a formal chemical conversion of enmein into ent-kaurene, atisine, garryiae and veatchine.
                                    使衍生自半球蛋白(2)的内酯5进行酰胆素缩合,得到18作为主要产物。化合物18转化为27,经
臭氧分解得到酮31。后者在液体NH 3中用Ca处理,得到3。这项工作构成了enmein到ent- kaurene,atisine,garryiae和veatchine的正式
化学转化。