[20451-53-0]  · C8H8OS  · Phenylsulfinylethylene  · (MW 152.23) (±)

[88180-53-4] (S)

[89299-86-4] (R)


(acetylene equivalent in Diels-Alder, dipolar cycloaddition, and Michael reactions; can be deprotonated to the unsaturated a-sulfinyl carbanion; undergoes additive Pummerer reactions)

Physical Data: bp 93-95 °C/0.2 mmHg; n20D 1.5865; d 1.139 g cm-3; (S)-(-): [a]20D -376° (c 1.0, MeOH).

Solubility: sol most organic solvents.

Form Supplied in: colorless liquid; commercially available.

Preparative Methods: racemic reagent can be prepared from dibromoethane in one pot by substitution with thiophenolate and elimination of HBr (50-65%), followed by oxidation (68-70%).2 The preparation of optically active phenylsulfinylethylene has been reported in a few instances only. It is noted, however, that optically active sulfoxides can be prepared by reaction of a carbanion with chiral arylsulfinates derived from menthol3a or glucose,3b or N-sulfinyloxazolidinones of norephedrine or phenylalanine,3c,d or by sequential arylation-vinylation of sulfites derived from lactic acid3e or aminosulfites derived from ephedrine (99+% ee).3f Alternatively, they can be prepared by enantioselective oxidation of sulfides with Sharpless-type reagents,3g,h oxaziridines,3i and by microbial oxidation.3j Finally, resolution is possible via cocrystallization with 1,1-binaphthol3k,1 or by chiral HPLC.3m

Purification: enantiomeric purity can be determined by 1H NMR using chiral solvating agents.3n

Handling, Storage, and Precautions: as with most optically active sulfoxides, optically active phenylsulfinylethylene racemizes in the presence of acids. Use in a fume hood.

Diels-Alder Reactions.

One use of phenylsulfinylethylene is as an acetylene equivalent in Diels-Alder reactions.4 Indeed, it is the only reagent of this type able to lose the activating functionality (phenylsulfenic acid) spontaneously after the cycloaddition.5 The examples in eqs 1 and 2 are representative.5,6

In most cases the reaction conditions needed for cycloaddition also cause desulfinylation of the adducts, but sometimes the primary cycloadduct can be isolated and subjected to different transformations. For example, adducts can be alkylated7a or transformed into a ketone (eq 3).7b In such cases, phenylsulfinylethylene can be considered an equivalent of allene or ketene in [4 + 2] cycloadditions. It is notable that phenylsulfinylethylene will react with deactivated dienes as cyclopentadienones,8a pyrones (eq 4),8b and thiophene dioxides (eq 5).9

A close relative of the title reagent, optically active tolylsulfinylethylene ([36832-47-0]; (±) [110455-66-8]; (R) [54828-68-1]; (S) [27328-17-2]), adds to cyclopentadiene with modest endo-exo and face selectivity.10 The stereochemistry of addition favors the endo-syn adduct (eq 6).7 The selectivity is improved if the sulfoxide is transformed into the oxysulfonium salt by alkylation with Meerwein reagent. In this case the product is the endo-anti adduct, but treatment with sodium hydroxide regenerates the sulfoxide with inversion of configuration, so that products identical to the cycloaddition of tolylsulfinylethylene itself are obtained.11a The method has been used to prepare the Corey prostaglandin intermediate (eq 7).11b

Dipolar Cycloadditions.

In view of the mild conditions of elimination, phenylsulfinylethylene can be used in the synthesis of heterocycles. For example, a- and b-nicotyrines12a and indolizines12b have been prepared using phenylsulfinylethylene as a dipolarophile. In asymmetric synthesis, the adducts formed between enantiomerically pure tolylsulfinylethylene and nitrones have been converted to optically active amino alcohols (eq 8),13a and with 1-methyl-3-oxidopyridinium to enantiomerically pure 2a-tropanol (eq 9).13b

Michael Additions.

Phenylsulfinylethylene can react as a Michael acceptor, as illustrated in eqs 10 and 11.14a,b In these instances the adducts have been subjected to the Pummerer reaction,15 but adducts can be simply heated to obtain the alkene. In the latter case, phenylsulfinylethylene functions as a vinyl cation equivalent.14c In one case the vinyl sulfoxide has been shown to cyclize to a cyclobutane (eq 12).16

Pummerer Reactions.15

Phenylsulfinylethylene reacts with Isopropenyl Acetate and catalytic p-Toluenesulfonic Acid to give phenylthioacetaldehyde via a presumed 3,3-sigmatropic shift (eq 13).17a Thionyl Chloride,17b Trifluoroacetic Anhydride,17c and Dichloroketene17d also react with the title reagent in additive-type Pummerer reactions. Pummerer-ene reactions occur in the presence of alkenes with formation of the products shown in eq 14.18

Reactions as Acids.

Strong bases such as Lithium Diisopropylamide deprotonate phenylsulfinylethylene to give the vinylic a-sulfinyl carbanion;19 the latter adds to aldehydes and ketones, e.g. with o-acetylphenols it affords 4-substituted chromans (eq 15).20

1. (a) De Lucchi, O.; Pasquato, L. T 1988, 44, 6755. (b) Posner, G. In The Chemistry of Sulphones and Sulphoxides; Patai, S.; Rappoport, Z.; Stirling, C. J. M. Eds.; Wiley: Chichester, 1988; Chap. 16, pp 823-850. (c) Kresze, G. MOC 1985, E11, 842.
2. (a) Paquette, L. A.; Carr, R. V. C. OS 1985, 64, 157. (b) Shimizugawa, Y.; Takahashi, T.; Ishii, M.; Yamamoto, T. OPP 1990, 22, 522.
3. (a) Andersen, K. K.; Gaffield, W.; Papanikolaou, N. E.; Foley, J. W.; Perkins, R. I. JACS 1964, 88, 5637. (b) Fernández, I.; Khiar, N.; Llera, J. M.; Alcudia, F. JOC 1992, 57, 6789. (c) Marino, J. P.; Bogdan, S.; Kimura, K. JACS 1992, 114, 5566. (d) Evans, D. A.; Faul, M. M.; Colombo, L.; Bisaha, J. J.; Clardy, J.; Cherry, D. JACS 1992, 114, 5977. (e) Rebiere, F.; Samuel, O.; Ricard, L.; Kagan, H. B. JOC 1991, 56, 5991. (f) Benson, S. C.; Snyder, J. K. TL 1991, 32, 5885. (g) Di Furia, F.; Modena, G.; Seraglia, R. S 1984, 325. (h) Pitchen, P.; Duñach, E.; Deshmukh, M. N.; Kagan, H. B. JACS 1984, 106, 8188. (i) Davis, F. A.; Reddy, R. T.; Han, W.; Carroll, P. J. JACS 1992, 114, 1428. (j) Ohta, H.; Matsumoto, S.; Okamoto, Y.; Sugai, T. CL 1989, 625. (k) Toda, F.; Mori, K. CC 1986, 1059. (l) Weber, E.; Wimmer, C.; Llamas-Saiz, A. L.; Foces-Foces, C. CC 1992, 733. (m) Saigo, K.; Nakamura, M.; Adegawa, Y.; Noguchi, S.; Hasegawa, M. CL 1989, 337. (n) Deshmukh, M. N.; Duñach, E.; Juge, S.; Kagan, H. B. TL 1984, 25, 3467.
4. De Lucchi, O.; Modena, G. T 1984, 40, 2585.
5. Paquette, L. A.; Moerck, R. E.; Harirchian, B.; Magnus, P. D. JACS 1978, 100, 1597.
6. (a) Miyahara, Y.; Inazu, T.; Yoshino, T. TL 1983, 24, 5277. (b) Ishii, A.; Nakayama, J.; Kazami, J.; Ida, Y.; Nakamura, T.; Hoshino, M. JOC 1991, 56, 78.
7. (a) Williams, R. V.; Chauhan, K. CC 1991, 1672. (b) Williams, R. V.; Lin, X. CC 1989, 1872.
8. (a) Jutzi, P.; Siemeling, U. CB 1989, 122, 993. Eguchi, S.; Ishiura, K.; Noda, T.; Sasaki, T. JOC 1987, 52, 496. (b) Pindur, U.; Erfanian-Abdoust, H. LA 1989, 1275. Jackson, P. M.; Moody, C. J. JCS(P1) 1990, 2156. Jackson, P. M.; Moody, C. J. T 1992, 48, 7447.
9. Nakayama, J.; Yamaoka, S.; Nakanishi, T.; Hoshino, M. JACS 1988, 110, 6598.
10. (a) Maignan, C.; Raphael, R. A. T 1983, 39, 3245. (b) Koizumi, T. PS 1991, 58, 111.
11. (a) Ronan, B.; Kagan, H. B. TA 1991, 2, 75. (b) Ronan, B.; Kagan, H. B. TA 1992, 3, 115.
12. (a) Mullen, G. B.; Georgiev, V. S. JOC 1989, 54, 2476. (b) Matsumoto, K.; Uchida, T.; Ikemi, Y.; Tanaka, T.; Asahi, M.; Kato, T.; Konishi, H. BCJ 1987, 60, 3645.
13. (a) Koizumi, T.; Hirai, H.; Yoshii, E. JOC 1982, 47, 4004. (b) Takahashi, T.; Kitano, K.; Hagi, T.; Nihonmatsu, H.; Koizumi, T. CL 1989, 597.
14. (a) Ono, N.; Miyake, H.; Tanikaga, R.; Kaji, A. JOC 1982, 47, 5017. (b) Chan, W. H.; Lee, A. W. M.; Chan, E. T. T. JCS(P1) 1992, 945. (c) van der Veen, R. H.; Cerfontain, H. JCS(P1) 1985, 661. Other examples of Michael addition to phenylsulfinylethylene: Ono, N.; Miyake, H.; Kamimura, A.; Tsukui, N.; Kaji, A. TL 1982, 23, 2957. Koppes, M. J. C. M.; Cerfontain, H. RTC 1988, 107, 412. Mandai, T.; Ueda, M.; Hasegawa, S.; Kawada, M.; Tsuji, J. TL 1990, 31, 4041. Opio, J. O.; Galons, L. H.; Miocque, M.; Zaparucha, A.; Loupy, A. SC 1991, 21, 1743. Craig, D.; Daniels, K.; MacKenzie, A. R. T 1992, 37, 7803.
15. De Lucchi, O.; Miotti, U.; Modena, G. OR 1991, 40, 157.
16. Haynes, R. K.; Loughlin, W. A.; Hambley, T. W. JOC 1991, 56, 5785.
17. (a) De Lucchi, O.; Marchioro, G.; Modena, G. CC 1984, 513. (b) Posner, G. H.; Asirvatham, E.; Ali, S. F. CC 1985, 542. (c) Craig, G.; Daniels, K.; MacKenzie, A. R. TL 1990, 31, 6441. (d) Marino, J. P.; Neisser, M. JACS 1981, 103, 7687.
18. Brichard, M.-H.; Janousek, Z.; Merényi, R.; Viehe, H. G. TL 1992, 33, 2511.
19. Cheng, H.-C.; Yan, T.-H. TL 1990, 31, 673.
20. Solladié, G.; Girardin, A. BSF(2) 1987, 123.

Ottorino De Lucchi

Università di Venezia, Italy

Giulia Licini

Università di Padova, Italy

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