An Example of Regioselective Fischer Indole Annulation
作者:Jens Christoffers
DOI:10.1055/s-2005-923605
日期:——
Bicyclo[n.4.0]alkan-3-ones (n = 3, 4, 5) with a trans bridge-head configuration give linear annulated tetrahydrocarbazole derivatives in Fischer indole synthesis. The structure of two tetrahydrocarbazoles was confirmed byX-ray crystal analysis. The hexahydroindanone derivative with a cis bridge-head configuration gives, contrastingly, the angular annulation product under the same reaction conditions
Fischerindolesynthesis with bicyclic ketones yields regioselectively linear annulated tetracyclic products when starting from ketones with a relative trans configuration. On the other hand, starting materials with a relative cis configuration give exclusively angular annulated indole derivatives. The starting materials were prepared in optically active form in three steps by a sequence of asymmetric