Résumé
The study of the reactivity of non-stabilized, semi-stabilized and stabilized lithium diphenylphosphonium diylides
1–
4 towards Ph
2PCl, allowed the synthesis of various α,β-unsaturated phosphines
13–
14, via the intermediate formation of the corresponding functionalized monoylides
9–
10 and their in situ reaction with carbonyl compounds. In many cases, the reaction is
Z-stereoselective and the created double bond can be di- or also trisubstituted. The precise
1H-NMR study of the phosphines
13a–
d and the X-ray analysis of
13a (
Z isomer) allowed us to assign without ambiguity the stereochemistry of these compounds and to solve a
1H-NMR question. Contrary to reported results in the literature for
13a, we have shown that for the double bond of this phosphine, there is no exception to the general rule
3
J
HH(
trans)>
3
J
HH(
cis). The extension of this reactivity study to other phosphorus electrophiles such as Ph
2P(O)Cl, Ph
2P(S)Cl and (EtO)
2P(O)Cl allowed, as preliminary results, the
E-stereoselective synthesis of styrylphosphine oxide and sulfide and diethyl styrylphosphonate.