Polyoxirannes et polythiirannes comportant un centre chiral dans la chaine latérale, 1. Synthèse et pureté optique de diastéréoisomères des époxy‐1,2 méthyl‐3 pentane et épithio‐1,2 méthyl‐3 pentane

In order to study the polymerization of oxiranes and thiiranes containing an asymmetric carbon atom in the side chain a mixture (mole ratio 1:1) of the diastereoisomers 2R,3S and 2S,3S 1,2‐epoxy‐3‐methylpentane (1a et 2a) and 2R,3S and 2S,3S 1,2‐epithio‐3‐methylpentane (1b et 2b) as well as the almost pure diastereoisomers 2R, 3S (1b) and 2S, 3S (2a) were prepared. The diastereoisomeric composition of these compounds was established by 1H NMR spectroscopy, at 250 MHz for the thiiranes and at 90 MHz for the oxiranes (in the presence of a chiral shift reagent). The optical activities of the different pure diastereoisomers were determined, and the chiroptical properties of these new monomers were studied.