REACTION OF 3-COORDINATE PHOSPHORUS-COMPOUNDS WITH ORGANOPHOSPHORUS PSEUDOHALOGENS .3. PHOSPHONIUM AND PHOSPHORANE INTERMEDIATES IN THE DESULFURIZATION AND DEOXYGENATION OF BIS(PHOSPHINOYL) DISULFIDES - INFLUENCE OF LEWIS-ACIDS ON THE REACTION CHEMOSELECTIVITY
E. Krawczyk et al., REACTION OF 3-COORDINATE PHOSPHORUS-COMPOUNDS WITH ORGANOPHOSPHORUS PSEUDOHALOGENS .3. PHOSPHONIUM AND PHOSPHORANE INTERMEDIATES IN THE DESULFURIZATION AND DEOXYGENATION OF BIS(PHOSPHINOYL) DISULFIDES - INFLUENCE OF LEWIS-ACIDS ON THE REACTION CHEMOSELECTIVITY, Journal of the Chemical Society. Perkin transactions. I, (1), 1994, pp. 89-99
The reactions of bis(phosphinoyl) disulfides RR(1)P(O)S-S-P(O)RR(1) 1
with P-III compounds have been investigated and various mechanistic fe
atures have been elucidated by variable-temperature P-31 NMR spectrosc
opy. These studies show that in most cases phosphonium intermediates [
drop P(O)-S-P(+)drop(-)O-P(S)drop] 5 and [drop P(S)-O-P(+)drop(-)O-P(S
)drop] 6 are involved. In cases where ligands on P-III increase the st
ability of the five-coordinate structures phosphorane intermediates ar
e observed. In the isomerization 5 --> 6, the mode of decomposition (d
esulfurization, deoxygenation or dealkylation) to give stable end prod
ucts is influenced by electronic and steric factors. The presence of t
he Lewis acid BF3 influences considerably the stability of the transie
nt species 5 and 6 and the chemoselectivity of the reaction.