ROTATION GENEE DANS LES YLURES DE PHOSPORE SUBSTITUES PAR UN GROUPEMENT F-ALKYL-2 ETHYL : MISE EN EVIDENCE PAR R.M.N. ET CRISTALLOGRAPHIE AUX RAYONS X
(F-alkyl-2 ethyl)triphenylcarboethoxymethylenephosphorane ylides show two different sets of ethyl protons in their 1H NMR spectra.We have formulated a hypothesis, and proved it by X ray diffraction, that this phenomena in solution was related to hindered