Synthesis of in, out-3,6,9,12,16,19,22,25,27,30,33,36-dodecaoxabicyclo[12.12.10]hexatriacontane and the chiral cryptand in, out-(–)-3,6,9,12,15,18,21,24,26,29,32-undecaoxabicyclo[12.10.9]tritriacontane. Out, in–in, out isomerism

Abstract

In, out-isomers of two macrobicyclic polyethers have been prepared by a specific route and have been shown by ¹³C n.m.r. spectroscopy to undergo in, out–out, in isomerization; in the case of the smaller cryptand, the interconversion may be slowed sufficiently by cooling for the bridgehead carbon atoms to be distinguished spectroscopically.