Triphenylphosphoranylidene ethenone

Versatile reagents in multi-component reactions 5.3.1. (Triphenylphosphoranylidene)ethenone 

Molteni and co-workers have described a further development of this reaction33. Similar to Westman and co-workers, Molteni et al. also performed the same type of multi-component reactions in a two-step manner, however they used water as the 

General reaction conditions 0.2 mmol, 1.2 equiv dinucleophiles, acetic acid/DMF 4 1, 180°C, 5 min. Tire LC-purity of tire products in the reaction mixture varied from 30 to 90% for this set of reactions. 

Example of a solid-phase synthesis of 1-phenyl-5-(4-phenoxyphenyl)-pyrazole, Reaction conditions (i) MeNH2 in water, 150°C, 10 min (ii) DMF, 180°C, 10 min (iii) HOAc, 180°C, 10 min. 

After additional washing, the resin was finally treated with 0.5 equiv of the appropriate dinucleophile (the resin-bound intermediate in excess) and reacted in ethanol, DMF or acetic acid at 180°C for 10 min. The resin was filtered off and the filtrate was evaporated to dryness to give the various heterocycles in yields of 88-94% and purities of 85-93%. 

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Dendrimer 27-[GJ can be used as the starting material for the grafting of ylides. Addition of triphenylphosphoranylidene ethenone Ph3P = C=C=0... 

Westman, J. and Orrling, K., Cascade synthesis with (triphenylphosphoranylidene)-ethenone as a versatile reagent for fast synthesis of heterocycles and unsaturated amides under microwave dielectric heating, Comb. Chem. High Throughput Screening, 2002, 5, 571-574. 

Treatment of a-hydroxymethylene ketones 646 with (triphenylphosphoranylidene)ethenone forms the intermediate ylide 647, which can undergo an intramolecular Wittig reaction to afford 2//-pyran-2-ones (Scheme 151) <1998T2161>. 

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