Identification des configurations relatives d'alcools secondaires α-cyclopropylidéniques et α-vinylcyclopropaniques. Attribution de structure aux éthyl-6 diméthyl-2,4 oxa-3 bicyclo [3.1.01,5]hexanes

During a stereochemical study of α-cyclic secondary alcohols, the relative configurations of the E, R*, and S* isomers of 1-(2-ethyl-3-ethylidene(1R*,2R*)cyclopropyl)ethanol was determined. Treatment in a basic medium of these secondary diastereomeric alcohols leads to the R* and S* isomers of 1-(2-ethyl-3-vinyl(1R*,2S*,3S*)cyclopropyl)ethanol. Cyclic oxymercuration of these cyclopropanoic derivatives yields the di-endo, di-exo, and exo–endo derivatives of 6-ethyl-2,4-dimethyl-3-oxabicyclo[3.1.0. 1,5 ]hexane. The determination of the structure as bicyclic ethers, based on ir and 1 H and 13 C nmr studies, permits the assignment of the relative configurations of the vinylcyclopropanoic and cyclopropylidene alcohols. [Journal translation]