Methoxymethylenetriphenylphosphorane

[20763-19-3] C20H19OP (MW 306.36) InChI = 1S/C20H19OP/c1-21-17-22(18-11-5-2-6-12-18,19-13-7-3-8-14-19)20-15-9-4-10-16-20/h2-17H,1H3 InChIKey = DYROHZMICXBUMX-UHFFFAOYSA-N (Wittig reagent for carbonyl homologation; vinyl ether synthesis1-8) Physical Data: deep red in solution; unstable at 25 °C.1-3 Solubility: sol organic solvents; decomposes in protic solvents, aldehydes, and ketones.1 Analysis of Reagent Purity: unstable at 25 °C, decomposing completely in <24 h producing PPh3 (70%; 31P NMR δ −5.1 ppm) and other unidentified species.2 The ylide gives a 31P NMR signal at δ 7.9 ppm (−90 °C) which is shifted upfield to 5.8 ppm (2JP–H = 48 Hz; 3JP–H = 12 Hz) at ambient temperatures. Preparative Methods: by the deprotonation of methoxymethyl(triphenyl)phosphonium chloride (from Triphenylphosphine/Chloromethyl Methyl Ether)4a,b with a number of bases (alkyllithiums, alkoxides, dimsylsodium, amides).4-8 Handling, Storage, and Precautions: should be generated in situ at low temperature (e.g. −90 °C) under a nitrogen atmosphere and used immediately.