The tris(dimethylamino)-C-dimethylphosphorus ylide and its supported version the tris(dimethylamino)phosphorus ylide C-bound to Merrifield's resin are strong non-nucleophilic bases (the pK a value of the conjugate acid has been estimated at 27 in THF). These compounds efficiently replace classical bases in the N-alkylation reaction of lactams, benzodiazepines, β-amino phosphine oxides and α-amino acid derivatives. They can be involved in the C-alkylation reaction of benzodiazepines, imines, lactams, succinimides, and β-enamines. They can also be used in base-catalysed aldol-type condensation (Henry) reactions of nitroethane with aldehydes, and in olefination reactions of phosphine oxides and phosphonates. (C) 2000 Academie des sciences/Editions scientifiques et medicales Elsevier SASbases / phosphorus ylides / phosphonium salts
Utilisation en synthese organique des ylures du phosphore comme bases fortes neutres et non-nucleophiles. Le tris(dimethylamino)-C-dimethylmethylene phosphorane et sa version greffee sur la resine de Merrifield sont des bases fortes non-nucleophiles (le pK a de l'acide conjugue a ete estime a 27 dans le THF). Ces composes remplacent efficacement les bases classiques pour les reactions de N-alkylation des lactames, des benzodiazepines, des oxydes de β-amino phosphines et des derives des α-aminoacides. Ils peuvent egalement etre utilises pour les reactions de C-alkylation des benzodiazepines, des imines, des lactames, des succinimides et des β-enamines. Ces bases peuvent egalement intervenir dans la reaction de condensation entre le nitroethane et les aldehydes (reaction de Henry) et dans les reactions de type Wittig-Horner ou Horner-Wadsworth-Emmons.