221454-70-2Relevant academic research and scientific papers
Synthesis of Novel D-Secoestrone Isoquinuclidines by an Unpredicted Iminium Ion-Induced 1,5-Hydride Shift
Woelfling, Janos,Frank, Eva,Schneider, Gyula,Tietze, Lutz F.
, p. 90 - 100 (2007/10/03)
Unique 9,13-bridged D-secoestrone alkaloids have been synthesized and structurally characterized. Treatment of 3-methoxy-16,17-secoestra-1,3,5(10)trien-17-al (6a) with aniline (7) or substituted aniline derivates 8-28 in the presence of different Lewis and Broensted acids produces the bridged azaestrone derivatives 51-67 and the alkenes 68-73 in high yields in a domino-type process. The imines 29-50 are proposed as intermediates, undergoing 1,5-hydride shifts via the iminium ion salts 75 to give the cations 77, which, depending on the substitution pattern on the aniline moiety, either afford the bridged compounds through a nucleophilic addition of the formed secondary amine to the benzylic carbocation or give the alkenes through the abstraction of a proton at C-8.
