High diastereoselectivity is observed in the preparation of configurationally stable allocolchicinoids 5 from Fischer carbene complexes 4 and 1-pentyne. The analogous reaction of complexes 8 gives 9 with moderate diastereoselectivity for the opposite atropisomer and this selectivity can be taken to high levels under thermodynamic conditions.
在从 Fischer 卡宾配合物 4 和
1-戊炔制备构型稳定的别秋
水仙素 5 中观察到高非对映选择性。配合物 8 的类似反应得到 9,对相反的阻转异构体具有中等的非对映选择性,在热力学条件下,这种选择性可以达到很高的
水平。