Facile synthesis of 12-carboxamido-11-spirostenes via palladium-catalyzed carbonylation reactions.
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.
Acs
Péter
P
University of Pécs, Department of Inorganic Chemistry, Ifjúság u.6., H-7624 Pécs, Hungary.
Müller
Erno
E
Czira
Gábor
G
Mahó
Sándor
S
Perreira
Mariette
M
Kollár
László
L
D002384:Catalysis; D007659:Ketones / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D010165:Palladium / Q000737:chemistry*; D013150:Spirostans / Q000138:chemical synthesis*
D007659:Ketones; D013150:Spirostans; D010165:Palladium