Nitrogen-Containing Tricyclic and Tetracyclic Compounds by Stereoselective Samarium Diiodide Promoted Cyclizations of Quinolyl-Substituted Ketones – A New Access to Azasteroids
作者:Francesca Aulenta、Ulrike K. Wefelscheid、Irene Brüdgam、Hans-Ulrich Reißig
DOI:10.1002/ejoc.200800019
日期:2008.5
withsamarium diiodidepromotedcyclizations of quinolyl-substitutedketones 6–12 and also the attempted reductive cyclization of carbazole-containing ketone 13. These precursors were prepared by Heck-type coupling reactions of the corresponding hetaryl nonaflates with adequately substituted olefins as a key step. The cyclization of compounds 7–12 led to nitrogen-containing tri- and tetracycliccompounds 23–28
An efficient synthesis of a series of quinolyl-substituted ketones or ketone precursors via the Heck reaction of 6- or 8-quinolyl nonaflates with an appropriate selection of olefins is presented. These ketones are useful building blocks for the diastereoselective construction of azapolycycles via SmI2-induced intramolecular cyclization of (het)aryl-substituted ketones.