1055036-47-9Relevant academic research and scientific papers
Synthesis of Chiral Hydroxylated Quinolizidines via Vinylogous Bischler-Napieralski Nitrilium Ion Cyclizations
Marquart, Angela L.,Podlogar, Brent L.,Huber, Edward W.,Demeter, David A.,Peet, Norton P.,et al.
, p. 2092 - 2100 (2007/10/02)
Treatment of the amido esters 9 and 17 with PPSE (polyphosphoric acid trimethylsilyl ester) followed by NaBH4 in ethanol gave the quinolizidinones 11-14 and 19 via a vinylogous Bischler-Napieralski nitrilium ion cyclization-reductive lactamization two-step process.Subsequent ozonolysis and reduction afforded chiral hydroxylated quinolizidines in moderate to good yield.In contrast to five-membered-ring formation, six-membered-ring formation via nitrilium-ion cyclization requires a p-methoxy-substituted styryl terminator.The effect para-substituted styryl terminators have on the energy of activation and ΔH for the cyclization process has been calculated by semiempirical and ab initio methods.
