Synthesis of α‐phosphonylated phosphonium and sulfonium ylides: Study of their thermal behavior

Abstract

ABSTRACT:The additions of two equivalents of trialkylphosphites onto phosphonodithioformates produce stabilized α-sulfanyl-α-phosphonyl phosphonium ylides. Their subsequent reaction with alkyl or benzyl halides gives stabilized sulfonium ylides. Thermal treatment of these phosphonium and sulfonium ylides leads to α-sulfanyl methylene bis-phosphonates through protonation-dealkylation intramolecular reactions.

Phosphonium salts and P-ylides

“…Hydrochloric treatment of either diastereoisomer of (91) was found to keep intact the two carbon-palladium bonds, affording the corresponding enantiomeric b-zwitterionic NHC-ylide palladate complexes (92). 144 The reaction of a mixed phosphine-phosphonium ylide, PPh 2 CH 2 (Ph 2 )P = C(H)C(O)Ph with mercury(II) halides yielded the P,C-chelate complexes (93). 145 As one can expect, in the reactions of the related phosphine-phosphonium salt, [PPh 2 CH 2 P þ Ph 2 CH 2 COPh]Br À , with mercury(II) halides the salt serves as a P-monodentate ligand to give zwitterionic mixed halogen mercurates (94).…”

“…The subsequent reaction of these ylides with alkyl or benzyl halides gives stabilized sulfonium ylides (59) while their heating (18-150 h, 110 o C) leads to a-sulfanyl methylene bis-phosphonates through protonation-dealkylation intramolecular reactions. 93 The synthesis of a stable and structurally-characterized sila-ylide (as a mixture of two diastereomers (60a) and (60b)) was accomplished via the reaction of a racemic 2-phosphinoenamine with magnesium in THF at room temperature. Interestingly, the reactivity of the sila-ylide towards aldehydes (Wittig olefination) was found to be similar to that of classical phosphonium ylides.…”