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Addition of secondary phosphines to phenylcyanoacetylene as a route to functional phosphines

 

作者: Boris A. Trofimov,  

 

期刊: Mendeleev Communications  (RSC Available online 1999)
卷期: Volume 9, issue 4  

页码: 163-164

 

ISSN:0959-9436

 

年代: 1999

 

出版商: RSC

 

数据来源: RSC

 

摘要:

Mendeleev Communications Electronic Version, Issue 4, 1999 (pp. 129–170) Addition of secondary phosphines to phenylcyanoacetylene as a route to functional phosphines Boris A. Trofimov, Svetlana N. Arbuzova,* Anastasiya G. Mal’kina, Nina K. Gusarova, Svetlana F. Malysheva, Mikhail V. Nikitin and Tamara I. Vakul’skaya Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, 664033 Irkutsk, Russian Federation.Fax: +7 3952 35 6046; e-mail: gusarova@irioch.irk.ru Bis(2-phenylethyl)phosphine 1a and bis(2-phenylpropyl)phosphine 1b react chemo- and regioselectively with phenylcyanoacetylene to give [bis(2-phenylalkyl)](1-phenyl-2-cyanoethenyl)phosphines 2 and 3 in quantitative total yields. Amphiphilic functional phosphines with polar hydrophilic groups and hydrophobic branched chains are promising ligands for the design of metal complex catalysts that combine the properties of phase-transfer and micellar catalysts.The synthesis of these phosphines is a topical problem. Here we report an approach to the synthesis of a new family of ternary arylalkylphosphines bearing an acrylonitrile substituent. The nucleophilic addition of bis(2-phenylethyl)phosphine 1a and bis(2-phenylpropyl)- phosphine 1b, which can be easily prepared from elemental phosphorus and arylalkenes,1 to phenylcyanoacetylene is used as an example.It is well known that cyanoacetylenes (primarily phenylcyanoacetylene) easily add N-, O- and S-nucleophiles [ammonia,2 piperidine,2 N-(tert-butyl)hydroxylamine,3 azoles,4 imidazolethiones5 and mercaptoquinolines6] to form, in most cases, Z-isomers of 3-substituted acrylonitriles.The reaction of secondary phosphines with cyanoacetylene proceeds in the same direction.7 However, there are no data on the interaction of phenylcyanoacetylene with PH species, while this reaction makes it possible not only to solve the above problem and to synthesise new functional organophosphorus compounds, but also to obtain additional information on the reactivity of disubstituted acetylenes. The aim of this work was to study the reaction of activated disubstituted acetylenes with secondary phosphines in order to determine its mechanism and chemo-, regio- and stereoselectivity.Scheme 1 demonstrates that phosphines 1a and 1b add readily to phenylcyanoacetylene giving new [bis(2-phenylalkyl)]- (1-phenyl-2-cyanoethenyl)phosphines 2 and 3 in almost quantitative total yields.† The process is chemo- and regioselective: neither 2-substituted acrylonitriles nor products of further addition of starting phosphine 1 to the double bond of compounds 2 and 3 (even with an excess of 1) were formed.The reaction of bis(2-phenylethyl)phosphine 1a with phenylcyanoacetylene proceeds stereoselectively to afford 2a; corresponding E-isomer 3a was formed in negligible amounts (~5%).This fact is in agreement with the trans-mode of nucleophile addition (in particular, P-nucleophiles7,8) to activated acetylenes.9 In contrast to phosphine 1a, more branched bis(2-phenylpropyl) phosphine 1b reacts with phenylcyanoacetylene to form not only the Z-isomer of [bis(2-phenylpropyl)](1-phenyl-2-cyanoethenyl) phosphine 2b, but also a considerable amount of the E-isomer of 3b (the ratio 2b:3b = 3:2).It is unlikely that phosphine 3b resulted from post-isomerization of phosphine 2b, which was formed initially, because the configurational transformation of Z-isomer 2b into E-isomer 3b has been found to occur on heating at 180–200 °C for 5 h.Therefore, the successful competition between the trans- and cis-addition to a triple bond occurs in the case of phosphine 1b because of steric hindrances. Note that the EPR spectrum of the reaction mixture of bis(2- phenylethyl)phosphine 1a and phenylcyanoacetylene in dioxane exhibits a high-resolution signal as a doublet of multiplets with g = 2.0029 and a doublet hyperfine structure constant of ~3 mT.This signal can be attributed10 to the interaction of an unpaired electron with the phosphorus nucleus; this fact indicates that the reaction can proceed via a stage of one-electron transfer. This presumption was also confirmed by UV spectra of the reaction mixture. These spectra exhibited a charge-transfer absorption band at 412 nm, which varied with time.11 At the same time, the addition of small amounts of hydroquinone (up to 3 wt%) to the reaction mixture had almost no effect on the product yields and the reaction time.This fact suggests that the reaction is a nucleophilic addition rather than a chain-radical process. It is likely that the reaction proceeds † General experimental techniques. 31P and 1H NMR spectra were measured on a Jeol-90Q spectrometer.IR spectra were recorded on a Specord 75-IR spectrometer. EPR spectra were studied on an SE/X-2547 EPR spectrometer equipped with an NMR magnetometer and a microwave frequency meter (Radiopan, Poland) at room temperature. UV spectra were recorded on a Specord UV-Vis spectrometer. For 2a (oil): 1H NMR (CDCl3) d: 1.96 (m, 4H, CH2P), 2.65 (m, 4H, CH2Ph), 5.81 (d, 1H, HC=C, 3JPH 16.2 Hz), 7.07–7.37 (m, 15H, Ph). 31P NMR (CDCl3) d: –13.2. For 3a: 31P NMR (CDCl3) d: –9.9. For 2b: 1H NMR (CDCl3) d: 1.23 (m, 6H, Me), 1.70 (m, 4H, CH2P), 2.66 (m, 2H, CHPh), 5.74 (d, 1H, HC=C, 3JPH 17.9 Hz), 7.19–7.35 (m, 15H, Ph). 31P NMR (CDCl3) d: –21.4, –22.4, –23.3. For 3b (oil): 1H NMR (CDCl3) d: 1.20 (m, 6H, Me), 1.72 (m, 4H, CH2P), 2.70 (m, 2H, CHPh), 5.34 (d, 1H, HC=C, 3JPH was too small to be determined), 7.20–7.35 (m, 15H, Ph). 31P NMR (CDCl3) d: –16.7, –16.8, –17.1. Three signals in the 31P NMR spectra of 2b and 3b can be explained by the presence of two asymmetrical centres in the molecules of these compounds). Satisfactory elemental analyses were obtained for phosphines 2 and 3. For 4 (it was identified in the mixture with 2a by 1H and 31P NMR spectroscopy): 1H NMR (CDCl3) d: 2.42 (m, 4H, CH2P), 2.90 (m, 4H, CH2Ph), 6.02 (d, 1H, HC=C, 3JPH 29.2 Hz), 7.19–7.37 (m, 15H, Ph). 31P NMR (CDCl3) d: 38.8. For 5: yield 71%, mp 70–74 °C (CHCl3–Et2O). 1HNMR ([2H6]acetone) d: 2.70 (d, 3H, Me, 2JPH 13.6 Hz), 3.00–3.50 (m, 8H, CH2P, CH2Ph), 6.93–7.61 (m, 16H, HC=C, Ph). 31P NMR ([2H6]acetone) d: 34.53. Found (%): C, 61.88; H, 5.80; I, 23.47; N, 2.73; P, 5.06.Calc. for C26H27INP (%): C, 61.07; H, 5.32; I, 24.83; N, 2.74; P, 6.06. In the IR spectra of compounds 1–5, an absorption band at 2210 cm–1 (nCºN) was present, and no absorption corresponding to CºC and CºN bonds of the initial phenylcyanoacetylene (2270 cm–1 with a shoulder) was observed. Scheme 1 Reagents and conditions: molar ratio 1:PhCºCCN = 1:1, dioxane, room temperature, 1.5 h (for 1a), 5 h (for 1b).(PhCHCH 2)2PH R PhC CCN C C H CN Ph (PhCHCH 2)2P C C CN H Ph (PhCHCH 2)2P R 3 2 a R = H b R = Me R 1Mendeleev Communications Electronic Version, Issue 4, 1999 (pp. 129–170) via an intermediate ion-radical pair which dissociates to only a small extent. The structure and configuration of phosphines 2 and 3 were confirmed by 1H and 31P NMR spectroscopy (from the 31P–1H coupling of an ethenyl group12) and also by chemical transformations.Thus, phosphine 2a was oxidised in air to [bis(2-phenylethyl)]( Z-1-phenyl-2-cyanoethenyl)phosphine oxide 4. In contrast to the majority of ternary phosphines, the oxidation of 2a proceeds slowly; this is probably due to a decrease in the electron density at the phosphorus atom as a result of the conjugation of its lone electron pair with the carbon-carbon double bond and next with the nitrile group.Upon the treatment of phosphine 2a with methyl iodide in dioxane at room temperature, methyl[bis(2-phenylethyl)](Z-1-phenyl-2-cyanoethenyl) phosphonium iodide 5 was prepared. This work was supported by the Russian Foundation for Basic Research (grant no. 98-03-32925a). References 1 B. A. Trofimov, L. Brandsma, S. N. Arbuzova, S. F. Malysheva and N. K. Gusarova, Tetrahedron Lett., 1994, 35, 7647. 2 Ch. Moyreu and M. Bongrad, Ann. Chim., 1920, 14, 5. 3 H. G. Aurich and K. Hahm, Chem. Ber., 1979, 112, 2769. 4 A. G. Mal’kina, Yu. M. Skvortsov, B. A. Trofimov, D.-S. D. Taryashinova, N. N. Chipanina, A. N.Volkov, V. V. Keiko, A. G. Proidakov, T. N. Aksamentova and E. S. Domnina, Zh. Org. Khim., 1981, 17, 2438 [J. Org. Chem. USSR (Engl. Transl.), 1981, 17, 2178]. 5 G. G. Skvortsova, N. D. Abramova, A. G. Mal’kina, Yu. M. Skvortsov, B. V. Trzhtsinskaya and A. I. Albanov, Khim. Geterotsikl. Soedin., 1982, 963 [Chem. Heterocycl. Compd. (Engl. Transl.), 1982, 736]. 6 L. V. Andriyankova, A. G. Mal’kina, A. I. Albanov and B. A. Trofimov, Zh. Org. Khim., 1997, 33, 1408 (Russ. J. Org. Chem., 1997, 1332). 7 R. G. Kostyanovsky and Yu. I. El’natanov, Izv. Akad. Nauk SSSR, Ser. Khim., 1983, 2581 (Bull. Acad. Sci. USSR, Div. Chem. Sci., 1983, 32, 2322). 8 B. A. Trofimov, N. K. Gusarova and L. Brandsma, Main Group Chemistry News, 1996, 4, 18. 9 J. I. Dickstein and S. I. Miller, in The Chemistry of the Carbon–Carbon Triple Bond, ed. S. Patai, Wiley, Chichester, 1978, part 2, p. 813. 10 V. V. Pen’kovskii, Usp. Khim., 1975, 44, 969 (Russ. Chem. Rev., 1975, 44, 449). 11 C. N. R. Rao, in Ultra-violet and Visible Spectroscopy Chemical Applications, Butterworths, London, 1961, p. 230. 12 M. Duncan and M. J. Gallagher, Org. Magn. Res., 1981, 15, 37. Received: 14th October 1998; Com. 98/1381 (8/08243J)

 



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