A new generation of “instant ylids”: Powder mixtures of phosphonium salts and potassium hydride as storable precursors to wittig reagents

✍ Scribed by Mirella El-Khoury; Qian Wang; Manfred Schlosser

• Book ID: 104255880
• Publisher: Elsevier Science
• Year: 1996
• Tongue: French
• Weight: 134 KB
• Volume: 37
• Category: Article
• ISSN: 0040-4039
• DOI: 10.1016/s0040-4039(96)02084-9

✦ Synopsis

Mixing a finely pulverized alkyltriphcnylphosphonium salt and potassium hydride in 1 : 1 molar ratio gives a ready-to-use powder the components of which react rapidly when tert-butyl methyl ether is added under stirring. When, in general after a few minutes, the generation of the (triphenylphosphonio)alkanide is complete, it can be intrnediately used for the Wittig ulefination of a cathonyl compound. Compared to sodium amide based "instant ylids", the new blends offer little advantage as long as simple phosphonium salts are ingredients but they extend considerably the shelf life of mixtures containing heterosubstituted derivatives such as methylthiomethyl-or picolyltriphenylphosphonium salts.