[14633-95-5]  · C21H19P  · Cyclopropylidenetriphenylphosphorane  · (MW 302.36)

(phosphorane for cyclopropylidenation of aldehydes and ketones;1 utilized in cyclobutanone synthesis;2 reagent applied to polyspirane synthesis3)

Physical Data: mp 103 °C (dec); d 1.21 g cm-3.

Solubility: sol THF, DME, DMSO.

Analysis of Reagent Purity: proton and heteronuclear NMR and X-ray data have been reported.4

Preparative Methods: see Cyclopropyltriphenylphosphonium Bromide.

Handling, Storage, and Precautions: cyclopropylidenetriphenylphosphorane is a fairly stable ylide, capable of withstanding elevated reaction temperatures of approximately 60-65 °C. The ylide is sensitive to moisture and air and should be freshly prepared under anhydrous conditions under an inert atmosphere.


The most frequent application of cyclopropylidenetriphenylphosphorane involves the cyclopropylidenation of aldehydes and ketones. The references cited in the Ylide Generation: Cyclopropylidenetriphenylphosphorane section under the reagent Cyclopropyltriphenylphosphonium Bromide provide examples of alkene formation. In addition, further examples of alkenation are available,5 including an application to propellane synthesis,1a generation of tetrasubstituted alkenes (reaction with ketones),6 and synthesis of a,b-unsaturated aldehydes and ketones incorporating a cyclopropylidene unit (eq 1).7

Cyclobutanone Synthesis.

Coupling cyclopropylidenetriphenylphosphorane with an aldehyde and subsequent oxidation with m-Chloroperbenzoic Acid produces a spiro epoxycyclopropane which rearranges to a cyclobutanone (eq 2).2,8

Cyclopropylidenetriphenylphosphorane as a Nucleophile.

Cyclopropylidenetriphenylphosphorane adds to polarized alkenes to generate spiro compounds incorporating two cyclopropyl rings.9 In addition, the ylide reacts with epoxides to yield 1-substituted cyclopropylphosphonium salts and with nitrile oxides to yield oxime substituted phosphonium salts (MeI workup) or spiro compounds incorporating a cyclopropyl ring on an azirine ring (thermal workup).10 Cyclopropylidenetriphenylphosphorane reacts with CO2 to generate the carboxylate phosphonium salt which decomposes under aqueous base and acid workup to cyclopropanecarboxylic acid.11

Cope Rearrangement.

Cyclopropylidenetriphenylphosphorane provides a unique substrate for studying the Cope rearrangement (eq 3).12

Diels-Alder Reaction.

Cyclopropylidenetriphenylphosphorane reacts with a,b-unsaturated aldehydes to generate dienes incorporating a cyclopropylidene unit. Subsequent reaction of these unstable dienes with dienophiles results in cyclopropyl substituted cyclohexenes (eq 4).13


Research in the synthesis of polyspirane systems has applied cyclopropylidenetriphenylphosphorane to the construction of these complex molecules.3

1. (a) Yamago, S.; Nakamura, E. T 1989, 45, 3081. (b) Also see references sited for ylide generation in Cyclopropyltriphenylphosphonium Bromide.
2. Baldwin, J. E.; Bonacorsi, S., Jr.; Carlson, R. G.; Graber, F. D. JOC 1993, 58, 981.
3. Giersig, M.; Wehle, D.; Fitjer, L.; Schormann, N.; Clegg, W. CB 1988, 121, 525 and references cited therein.
4. (a) Albright, T. A.; Gordon, M. D.; Freeman, W. J.; Schweizer, E. E. JACS 1976, 98, 6249. (b) Schmidbaur, H.; Schier, A.; Milewski-Mahrla, B.; Schubert, U. CB 1982, 115, 722.
5. (a) McMurry, J. E.; Erion, M. D. JACS 1985, 107, 2712. (b) Moody, C. J.; Warrellow, G. J. JCS(P1) 1987, 913.
6. (a) Tarakanova, A. V.; Baranova, S. V.; Pekhk, T.; Dogadin, O. B.; Zefirov, N. S. ZOR 1987, 23, 515 (JOU 1987, 23, 464). (b) Van den Heuvel, C. J. M.; Steinberg, H.; DeBoer, T. J. RTC 1985, 104, 145. (c) Donskaya, N. A.; Akhochansakaya, T. V.; Leonova, T. V.; Shulishov, E. V.; Shabarov, Y. S. ZOR 1980, 16, 563 (JOU 1980, 16, 487). (d) Donskaya, N. A.; Akhochansakaya, T. V.; Shabarov, Y. S. ZOR 1976, 12, 1596 (JOU 1976, 12, 1572).
7. (a) Lechevallier, A.; Huet, F.; Conia, J. M. T 1983, 39, 3307. (b) Rousseau, G.; Lechevallier, A.; Huet, F.; Conia, J. M. TL 1978, 3287. (c) Huet, F.; Lechevallier, A.; Conia, J. M. TL 1977, 2521. (d) Reichardt, C.; Pressler, W.; Würthwein, E.-U. AG 1976, 88, 88.
8. Crandall, J. K.; Conover, W. W. JOC 1978, 43, 3533.
9. Kaupp, G.; Frey, H.; Behmann, G. CB 1988, 121, 2127.
10. Bestmann, H. J.; Denzel, T.; Kunstmann, R.; Lengyel, J. TL 1968, 2895.
11. Bestmann, H. J.; Denzel, T.; Salbaum, H. TL 1974, 1275.
12. (a) Kaufmann, D.; de Meijere, A. CB 1984, 117, 1128. (b) Kaufmann, D.; de Meijere, A. TL 1979, 783.
13. (a) Kulkarni, Y. S.; Snider, B. B. OPP 1986, 18, 7. (b) Kienzle, F.; Stadlwieser, J.; Mergelsberg, I. HCA 1989, 72, 348.

Edward J. Adams

E. I. DuPont de Nemours, Newark, DE, USA

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