Facile synthesis of 12-carboxamido-11-spirostenes via palladium-catalyzed carbo...

• Author(s): Ács, Péter ; Müller, Erno ; Czira, Gábor ; Mahó, Sándor ; Perreira, Mariette ; Kollár, László
• Date: 2006
• Persistent ID: http://hdl.handle.net/10316/5072
• Origin: Estudo Geral - Universidade de Coimbra
• Subject(s): Iodo-alkenene; Carboxamide; Hecogenin; Palladium-catalyst; Carbonylation
• Document Type: Article
• Language: English

Description

12-Carboxamido- and 12-carboxyl-11-spirostenes were synthesized from the corresponding 12-iodo-11-ene derivative in palladium-catalyzed carbonylation reactions under mild reaction conditions. The synthesis of the iodo-alkene substrate is based on the transformation of the 12-keto derivative (hecogenin) to hydrazone, which was treated with iodine in the presence of a base (1,1,3,3-tetramethyl guanidine). While various 12-carboxamides were synthesized in moderate to high yields by using simple alkyl/arylamines or amino acid methylesters as N-nucleophiles, low yields can be achieved with alcohols as O-nucleophiles. The homogeneous carbonylation reactions tolerate the 3-hydroxy substituent and the spiroacetal moiety. http://www.sciencedirect.com/science/article/B6TC9-4KBX4P7-1/1/9ccb758281b9b11e5e0e07e137f9015f