SYNLETT
Accounts and Rapid Communications in Synthetic Organic Chemistry
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Thieme
REPRINT
Zn/RuCl3-Promoted Cleavage of Diselenides: An Efficient Michael Addition of Zinc Selenolates to Conjugated Alkenes in Aqueous Media Zn/RuCl3-PromotedCleav geofDisel nides Barahman Movassagh,*a,b Ameneh Tatara a
Department of Chemistry, K. N. Toosi University of Technology, P.O. Box, 16315-1618, Tehran, Iran Kermanshah Oil Refining Company, Kermanshah, Iran Fax +98(21)22853650; E-mail:
[email protected] Received 15 March 2007 b
Abstract: A simple and highly efficient one-pot route to b-selenocarbonyl compounds and nitriles has been developed by Zn/RuCl3catalyzed cleavage of diselenides and subsequent Michael addition of zinc selenolates to conjugated alkenes in aqueous media. Key words: zinc selenolates, Michael addition, a,b-unsaturated carbonyl compounds, zinc, diselenides
R1SeSeR1 1
Zn/RuCl3 MeCN–H2O, 80 °C
[(R1Se)2Zn] 2
3
X
X R1Se
4
1
R = aryl, benzyl X = COR2, CHO, CO2R2, CN R2 = alkyl
Scheme 1
Over the last three decades, many investigators have described important chemical transformations that were efficiently achieved using organoselenium reagents. Organoselenium compounds are of considerable interest because of their involvement as key intermediates in organic synthesis and use as a food supplement.1 These compounds are no longer systematically classified as toxic and, thus, much effort is being devoted to accomplishing the synthesis of organic selenides. Although numerous reports on the synthesis of organoselenium compounds have already been published,1,2 most of them, with the exception of three recent reports,3 usually require the handling of unstable reagents, strongly acidic or basic reaction conditions, and two-step procedures. Hence, the development of a one-pot synthetic method using stable reagents under neutral conditions is in demand. Reductive cleavage of Se–Se bonds, especially cleavage of diphenyl or other diaryl diselenides, has attracted considerable attention due to the fact that selenide anion formed can be used for preparation of wide variety of compounds. Several reducing agents, including LiAlH4, NaBH4, Bu3SnH, and Na/NH3, have been introduced for Se–Se bond cleavage.4 Organometallic reactions in aqueous media have attracted considerable attention in organic synthesis.5 Recently, transition-metal selenolates or complexes have been widely used in synthesis of organoselenium compounds,6 but reports exploring zinc selenolates are rare.3a,7 As a part of our interest in zinc chemistry,7,8 we are in constant search for novel applications of zinc selenolates and zinc thiolates in chemical reactions. In the present paper we describe the use of zinc metal–ruthenium(III) chloride (Zn/ RuCl3)3a system for the cleavage of diselenides and in situ Michael addition of selenolate anion to a,b-unsaturated SYNLETT 2007, No. 12, pp 1954–195624.07207 Advanced online publication: 25.06.2007 DOI: 10.1055/s-2007-984495; Art ID: D07607ST © Georg Thieme Verlag Stuttgart · New York
carbonyl compounds and nitriles to give the corresponding b-selenocarbonyl compounds and nitriles (Scheme 1). Simple stirring of diselenides 1 with metallic zinc dust in the presence of ruthenium(III) chloride (10 mol%) in MeCN–H2O (4:1) mixed solvent at 80 °C produced the zinc selenolate 2. This was followed by addition of a,bunsaturated carbonyl compounds and nitriles 3 which gave, after workup, the desired product 4 with yields ranging from 55–98% (Table 1).9 Both diaryl and dialkyl (dibenzyl) diselenides react with a variety of conjugated alkenes by this procedure to produce the corresponding adducts. The conjugated alkenes include a,b-unsaturated ketones, aldehydes, carboxylic esters, and nitriles. The reaction of diaryl diselenides with methyl vinyl ketone (Table 1, entries 1 and 11) took place faster with higher yields than the others. a,b-Unsaturated carbonyl compounds and nitriles having substituents at either the a(Table 1, entry 7) or the b-position (Table 1, entries 2, 3, 5, and 10) show lower yields than the unsubstituted derivatives. Synthetically, preparation of a,b-phenylseleno carbonyl compounds enables a number of useful transformations based on the syn-elimination of phenyl selenoxide10 to be performed. In conclusion, this Zn/RuCl3-promoted one-pot procedure for the Michael addition of diselenides to conjugated alkenes in aqueous media provides an efficient methodology for the synthesis of b-selenocarbonyl compounds and nitriles. This method offers significant advantages with regards to operation, yield, time, handling of catalysts, and cost and thus presents an alternative to the existing procedures.11
is a copy of the author's personal reprint l
LETTER
l This
1954
LETTER
Zn/RuCl3-Promoted Cleavage of Diselenides
1955
Table 1 Reductive Cleavage of Diselenides and Conjugated Addition to Michael Acceptors in the Presence of Zn/RuCl3 System in MeCN–H2O Entry 1
R1
Alkene
Ph
Time (h)
COMe
Yield (%)a,b
Product COMe
1.25
9611b
PhSe O
O
2
Ph
6411b
3 SePh
3
COMe
Ph
4.5
Ph
4
Ph
PhSe
COMe
7111b
CHO
8712
Ph CHO
2.5 PhSe
5
Ph
6
Ph
CHO
CN
2.5
PhSe
3.25
CHO
7612
CN
8111a
CN
7511a
COOEt
8011a
COOn-Bu
7311c
PhSe
7
Ph
CN
3.5 PhSe
8
Ph
COOEt
3 PhSe
9
Ph
COOn-Bu
Ph
COOi-Pr
3.5 PhSe
10
COOi-Pr
4.75
5511a
PhSe COMe
11
4-ClC6H4
COMe
1
98 RSe
R = 4-ClC6H4 COMe
12
Bn
COMe
3.75
RSe
81
R = Bn a b
Yields refer to those of pure isolated products characterized by IR, 1H NMR, and 13C NMR spectroscopy. References for known compounds.
Acknowledgment We thank the K. N. Toosi University of Technology Research Council and Kermanshah Oil Refining Company for financial support.
References and Notes (1) (a) Krief, A.; Hevesi, L. Organoselenium Chemistry, Vol. 1; Springer: Berlin, 1988. (b) Krief, A. In Comprehensive Organometallic Chemistry; Trost, B. M., Ed.; Pergamon: Oxford, 1991, 85; and references therein. (2) (a) Patai, S.; Rappoport, Z. The Chemistry of Organic Selenium and Tellurium Compounds, Vol. 1; Wiley and Sons: New York, 1986. (b) Krief, A.; Derock, M. Tetrahedron Lett. 2002, 43, 3083. (c) Patai, S.; Rappoport, Z. The Chemistry of Organic Selenium and Tellurium Compounds, Vol. 2; Wiley and Sons: New York, 1987. (d) Paulmier, C. Selenium Reagents and Intermediates in Organic Synthesis; Pergamon: Oxford, 1986.
(3) (a) Zhao, X.; Yu, Z.; Yan, S.; Wu, S.; Liu, R.; He, W.; Wang, L. J. Org. Chem. 2005, 70, 7338. (b) Nishino, T.; Okada, M.; Kuroki, T.; Watanabe, T.; Nishiyama, Y.; Sonoda, N. J. Org. Chem. 2002, 67, 8696. (c) Ranu, B. C.; Mandal, T.; Samanta, S. Org. Lett. 2003, 5, 1439. (4) (a) Bhasin, K. K.; Singh, N.; Kumar, R.; Deepali, D. G.; Mehta, S. K.; Klapoetke, T. M.; Crawford, M.-J. J. Organomet. Chem. 2004, 689, 3327. (b) Yoshimatsu, M.; Sato, T.; Shimizu, H.; Hori, M.; Kataoka, T. J. Org. Chem. 1994, 59, 1011. (c) Crich, D.; Grant, D. J. Org. Chem. 2005, 70, 2384. (d) Andreadou, I.; Menge, W. M. P. B.; Commandeur, J. N. M.; Worthington, E. A.; Vermeulen, N. P. E. J. Med. Chem. 1996, 39, 2040. (e) Sakakibara, M.; Katsumata, K.; Watanabe, Y.; Toru, T.; Ueno, Y. Synthesis 1992, 377. (5) (a) Lubineau, A.; Auge, J.; Queneau, Y. Synthesis 1994, 741. (b) Li, C. J. Chem. Rev. 1993, 93, 2023.
Synlett 2007, No. 12, 1954–1956
© Thieme Stuttgart · New York
1956
B. Movassagh, A. Tatar
(6) (a) Meunier, P.; Gaotheron, B.; Mazouz, A. J. Chem. Soc., Chem. Commun. 1986, 424. (b) Osuka, A.; Ohmasa, N.; Suzuki, H. Synthesis 1982, 857. (c) Bao, W.; Zhang, Y. Synth. Commun. 1995, 25, 1825. (7) (a) Movassagh, B.; Mirshojaei, F. Monatsh. Chem. 2003, 134, 831. (b) Movassagh, B.; Shamsipoor, M. Synlett 2005, 121. (c) Movassagh, B.; Shamsipoor, M. Synlett 2005, 1316. (d) Movassagh, B.; Shamsipoor, M.; Joshaghani, M. J. Chem. Res., Synop. 2004, 148. (e) Movassagh, B.; Fazeli, A. Z. Naturforsch., B: Chem. Sci. 2006, 61, 194. (8) (a) Movassagh, B.; Zakinezhad, Y. Chem. Lett. 2005, 34, 1330. (b) Movassagh, B.; Mossadegh, A. Synth. Commun. 2004, 34, 1685. (c) Movassagh, B.; Zakinezhad, Y. Z. Naturforsch., B: Chem. Sci. 2006, 61, 47. (d) Lakouraj, M. M.; Movassagh, B.; Fadaei, Z. Synth. Commun. 2002, 32, 1237. (9) 4-(4-Chlorophenylseleno)butan-2-one – Typical Procedure In a typical experiment, a mixture of bis(4-chlorophenyl)diselenide (190 mg, 0.5 mmol), zinc dust (229 mg, 3.5 mmol), and ruthenium(III) chloride hydrate (13 mg, 0.05 mmol) was suspended in MeCN (8 mL) and H2O (2 mL). The mixture was stirred at 80 °C for 1.5 h, during which time the zinc powder was almost completely consumed. Then, methyl vinyl ketone (73 mg, 1.05 mmol) was added at once to the mixture and stirring was continued at that temperature for 1 h in air. After completion of the reaction, the solution was filtered, the solvent was evaporated, and the residue was
Synlett 2007, No. 12, 1954–1956
© Thieme Stuttgart · New York
LETTER subjected to preparative TLC (silica gel, eluent, n-hexane– EtOAc = 4:1) to afford pure 4-(4-chlorophenylseleno)butan2-one (255 mg, 98%, Table 1, entry 11) as a pale yellow oil. IR (neat): 1720, 1478, 739 cm–1. 1H NMR (300 MHz, CDCl3): d = 2.14 (s, 3 H), 2.84 (t, 2 H, J = 7.2 Hz), 3.05 (t, 2 H, J = 7.2 Hz), 7.25 (d, 2 H, J = 8.5 Hz), 7.42 (d, 2 H, J = 8.5 Hz) ppm. 13C NMR (75 MHz, CDCl3): d = 20.8, 30.0, 43.9, 127.9, 129.3, 133.3, 134.3, 206.8 ppm. MS: m/z (%) = 264 (46) [(M + 4]+ , 262 (90) [M + 2]+, 260 (49) [M+], 219 (15), 191 (20), 151 (24), 71 (55), 43 (100). Anal. Calcd for C10H11ClOSe: C, 45.91; H, 4.24. Found: C, 46.30; H, 4.51. Spectroscopic Data for Entry 12, Table 1 IR (neat): 1710, 1478, 738 cm–1. 1H NMR (500 MHz, CDCl3): d = 2.13 (s, 3 H), 2.69–2.71 (m, 2 H), 2.74–2.77 (m, 2 H), 3.84 (s, 2 H), 7.24–7.33 (m, 5 H) ppm. 13C NMR (125 MHz, CDCl3): d = 17.0, 28.1, 30.4, 44.7, 127.2, 128.9, 129.3, 139.7, 207.6 ppm. MS: m/z (%) = 242 (30) [M + 2]+, 240 (16) [M+], 181 (10), 91 (100), 65 (22), 43 (51). Anal. Calcd for C11H14OSe: C, 54.78; H, 5.85. Found: C, 54.51; H, 5.64. (10) Sevrin, M.; Krief, A. Tetrahedron Lett. 1978, 187. (11) (a) Ranu, B. C.; Das, A. Adv. Synth. Catal. 2005, 347, 712. (b) Miyashita, M.; Yoshikoshi, A. Synthesis 1980, 664. (c) Zhou, L.-H.; Zhang, Y.-M. Synth. Commun. 1999, 29, 533. (d) Detty, M. R. Tetrahedron Lett. 1978, 5087. (12) Nishiyama, Y.; Asano, T.; Kishimoto, Y.; Itoh, K.; Ishii, Y. Tetrahedron Lett. 1998, 39, 8685.