A biomimetic approach to the Elaeocarpus alkaloids. Syntheses of (.+-.)-elaeokanine A, (.+-.)-elaeokanine C, (.+-.)-elaeocarpidine, and (.+-.)-tarennine
A biomimetic approach to the Elaeocarpus alkaloids. Syntheses of (.+-.)-elaeokanine A, (.+-.)-elaeokanine C, (.+-.)-elaeocarpidine, and (.+-.)-tarennine
Aliphatic azidonitriles separated by three or four carbon atoms undergo facile Lewis acid-induced cycloadditions to give bicyclic tetrazoles, even at 0 degrees C. Extension to 3-azido-2-aryl-1,3-dioxolanes and the corresponding 1,3-dioxanes in the presence of TMSCN and BF3 center dot OEt2 leads to a series of diversely functionalized novel oxabicyclic tetrazoles. The reactions represent new aspects of proximity-assisted dipolar cycloadditions that afford thermodynamically controlled enantiopure products proceeding through discrete oxocarbenium ion intermediates.
GRIBBLE, GORDON W.;SWITZER, FRANK L.;SOLL, RICHARD M., J. ORG. CHEM., 53,(1988) N 14, 3164-3170
作者:GRIBBLE, GORDON W.、SWITZER, FRANK L.、SOLL, RICHARD M.