Quantitative determination of conformational equilibrium in quinolizidine-piperidine alkaloids. Part 2: Synthesis and conformational study of N-methylalbine
作者:Waleria Wysocka、Tadeusz Brukwicki
DOI:10.1016/j.tet.2003.09.002
日期:2003.10
boat ring C in the conformational equilibrium in 5 in benzene solution was determined to be ca. 22% using coupling constant J9–11β. The reason of the occurrence of a significant amount of the boat conformer is, similarly to N-methylangustifoline (2), the interaction of an axial allyl group with the bridge H8α hydrogen atom. The smaller fraction of the boat conformation in 5 than in 2 is caused by the