| Abstract
| - Lewis acid-directed cyclocondensations of piperidone enol ethers with 2-methoxy-4-(N-phenylsulfonyl)-1,4-benzoquinoneimine are reported. Benzofurans are obtained with BF3·OEt2 as a promoter,whereas use of excess amounts of TiCl4:Ti(OiPr)4 leads to tetrahydrocarbolines. The latter reactionsprovide expedient routes to oxygen-substituted tetrahydrocarbolines and carbolines. As applicationsof this new methodology, the preparations of 1-[3-(dimethylamino)propyl]amino-7-methoxy- and1-[3-(dimethylamino)propyl]amino-7,8-dimethoxy-5H-pyrido[4,3-b]indoles are described.
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