Enantioselective Michael Addition of a Malonic Ester to a Maleic Ester Catalyzed by Lithium Binaphtholate

Abstract

Lithium 3,3′-chlorobinaphtholate was found to catalyze the enantioselective Michael addition of a malonic ester to a maleic ester. High enantioselectivities (>90% ee) were observed, especially in the reactions of 2-alkylmalonic esters and maleic esters.

Key words

asymmetric catalyst - asymmetric synthesis - enantioselectivity - Michael addition - chiral catalyst - lithium binaphtholate

• References and Notes


Review for the enantioselective Michael addition:
• 1a Christoffers J, Koripelly G, Rosiak A, Rössle M. Synthesis 2007; 1279
• 1b Tsogoeva SB. Eur. J. Org. Chem. 2007; 1701
• 1c Almasi D, Alonso DA, Nájera C. Tetrahedron: Asymmetry 2007; 18: 299
• 1d Matsunaga S In Comprehensive Chirality . Vol. 4. Carreira EM, Yamamoto H. Elsevier; Amsterdam: 2012: 243
• 1e Takemoto Y, Stadler M In Comprehensive Chirality . Vol. 6. Carreira EM, Yamamoto H. Elsevier; Amsterdam: 2012: 243
• 2 Clarke HT, Murray TF. Org. Synth., Coll. Vol. I 1941; 272
• 3 Kotani S, Moritani M, Nakajima M. Asian J. Org. Chem. 2015; 4: 616

Lithium binaphtholate catalyzed reactions developed in our group:
• 4a Tanaka K, Kukita K, Ichibakase T, Kotani S, Nakajima M. Chem. Commun. 2011; 47: 5614
• 4b Ichibakase T, Nakatsu M, Nakajima M. Molecules 2011; 16: 5008
• 4c Ichibakase T, Nakajima M. Org. Lett. 2011; 13: 1579
• 4d Ichibakase T, Nakajima M. Synthesis 2012; 44: 3145
• 4e Ichibakase T, Kaneko T, Orito Y, Kotani S, Nakajima M. Tetrahedron 2012; 68: 4210
• 4f Kotani S, Kukita K, Tanaka K, Ichibakase T, Nakajima M. J. Org. Chem. 2014; 79: 4817
• 4g Osakama K, Nakajima M. Org. Lett. 2016; 18: 236

Selected examples of lithium binaphtholate-catalyzed asymmetric reactions:
• 5a Schiffers R, Kagan HB. Synlett 1997; 1175
• 5b Loog O, Maeorg I. Tetrahedron: Asymmetry 1999; 10: 2411
• 5c Holmes IP, Kagan HB. Tetrahedron Lett. 2000; 41: 7453
• 5d Hatano M, Ishihara K. Synthesis 2010; 3785
• 5e Hatano M, Horibe T, Ishihara K. J. Am. Chem. Soc. 2010; 132: 56
• 5f Hatano M, Ikeno T, Miyamoto T, Ishihara K. J. Am. Chem. Soc. 2010; 132: 56

Selected reports for the catalytic asymmetric Michael additions using alkli metal salts of binaphthol derivatives:
• 6a Tamai Y, Kamifuku A, Koshiishi E, Miyano S. Chem. Lett. 1995; 957
• 6b Kim YS, Matsunaga S, Das J, Sekine A, Ohshima T, Shibasaki M. J. Am. Chem. Soc. 2000; 122: 6506
• 6c Belokon YN, Gugkaeva ZT, Maleev VI, Moskalenko MA, Tsaloev AT, Khrustalev VN, Hakobyan KV. Tetrahedron: Asymmetry 2011; 22: 167
• 6d Otani T, Sugawara A, Tamai Y. Tetrahedron Lett. 2014; 55: 4923
• 7 Lithium salt prepared from the corresponding naphthol and lithium hydroxide gave lesser result (68% yield, 75% ee under the conditions given in Table 1, entry 7).
• 8 Typical Experimental Procedure for the Enantioselective Michael Addition Catalyzed by Lithium Binaphtholate Under argon atmosphere, n-BuLi (0.10 mmol, 20 mol%) in hexane (0.15 M, 0.67 mL) was added to the solution of (R)-Cl₂BINOL (4a, 17.8 mg, 0.050 mmol, 10 mol%) in TBME at r.t. After stirring for 1 min, dibenzyl malonate (1a, 0.13 mL, 0.5 mmol) and diethyl maleate (2a, 0.10 mL, 0.6 mmol, 1.2 equiv) were successively added to the reaction mixture. After stirring for 1 h, the reaction was quenched with sat. NH₄Cl aq (2 mL). The aqueous layer was extracted with EtOAc (20 mL), and the combined organic layers were washed with brine (20 mL). After drying over Na₂SO₄, filtration, and concentration, the crude product was purified by silica gel column chromatography (hexane–EtOAc = 9:1, SiO₂ 10 g) to give the adduct 3aa as a colorless oil (214 mg, 94% yield, 90% ee). [α]₄₃₅ ²⁷ +11.5 (c 1.03, CHCl₃) for 90% ee. IR (film): 3066, 3033, 1731, 1159 cm^–1. ¹H NMR (400 MHz, CDCl₃): δ = 1.15 (t, J = 7.2 Hz, 3 H, CH ₂CH₃), 1.23 (t, J = 7.6 Hz, 3 H, CH ₂CH₃), 2.66 (dd, J = 17.0, 5.2 Hz, 1 H, CH₂CO), 2.79 (dd, J = 17.0, 7.6 Hz, 1 H, CH₂CO), 3.60–3.62 (m, 1 H), 4.04–4.12 (m, 5 H), 5.14 (s, 2 H, CH₂Ph), 5.15 (s, 2 H, CH₂Ph), 7.28–7.37 (m, 10 H, ArH). ¹³C NMR (100 MHz, CDCl₃): δ = 13.8, 14.1, 33.4, 40.4, 52.3, 60.8, 61.4, 67.4, 128.2, 128.3, 128.4 128.5, 134.9, 135.0, 167.3, 167.5, 171.1, 171.5 (3 C overlapped). MS–FAB: m/z = 457 (M + H⁺), 91. HRMS: m/z calcd for C₂₅H₂₉O₈: 457.1862; found: 457.1868.

Recent examples of enantioselective Michael addition to maleimide derivatives:
• 9a Ye W, Jiang Z, Zhao Y, Goh SL. M, Leow D, Soh Y.-T, Tan C.-H. Adv. Synth. Catal. 2007; 349: 2454
• 9b Gómez-Torres E, Alonso DA, Gómez-Bengoa E, Nájera C. Org. Lett. 2011; 13: 6106

Selected examples of recent enantioselective Michael addition of malonate to chalcone:
• 10a Evans DA, Rovis T, Kozlowski MC, Downey CW, Tedrow JS. J. Am. Chem. Soc. 2000; 122: 9134
• 10b Ooi T, Ohara D, Fukumoto K, Maruoka K. Org. Lett. 2005; 7: 3195
• 10c Wang J, Li H, Zu L, Jiang W, Xie H, Duan W, Wang W. J. Am Chem. Soc. 2006; 128: 12652
• 10d Naka H, Kanase N, Ueno M, Kondo Y. Chem. Eur. J. 2008; 14: 5267
• 10e Agostinho M, Kobayashi S. J. Am Chem. Soc. 2008; 130: 2430
• 10f Wascholowski V, Knudsen KR, Mitchell CE. T, Ley SV. Chem. Eur. J. 2008; 14: 6155
• 10g Chen D, Chen Z, Xiao X, Yang Z, Lin L, Liu X, Feng X. Chem. Eur. J. 2009; 15: 6807
• 10h Mase N, Furusawa M, Kitagawa N, Shibagaki F, Nishiro N, Takabe K. Synlett 2010; 2340
• 10i Mao Z, Jia Y, Li W, Wang L. J. Org. Chem. 2010; 75: 7428
• 10j Yoshida M, Narita M, Hara S. J. Org. Chem. 2011; 76: 8513
• 10k Espinosa M, Blay G, Cardona L, Pedro JR. Chem. Eur. J. 2013; 19: 14861
• 10l Tsubo T, Yamada T. Synlett 2015; 26: 1111
• 10m Lippur K, Kaabel S, Järvibg I, Rissanen K, Kanger T. J. Org. Chem. 2015; 80: 6336
• 11 See ref. 10m for the only example for the enantioselective Michael addition to fumarate.
• 12 Recent examples of the enantioselective Michael addition to diphenyl butenedione: Zari S, Kailas T, Kudrjashova M, Öeren M, Järving I, Tamm T, Lopp M, Kanger T. Beilstein J. Org. Chem. 2012; 8: 1452
• 13 Compound 3ea (Representative Product) [α]_D ²⁹ –11.4 (c 1.0, CHCl₃) for 98% ee. IR (ATR): 2983, 1728, 1213 cm^–1. ¹H NMR (400 MHz, CDCl₃): δ = 1.16 (t, J = 7.2 Hz, 3 H, CH₂CH ₃), 1.24 (t, J = 7.6 Hz, 3 H, CH₂CH ₃), 1.50 (s, 3 H, CCH₃), 2.56 (dd, J = 16.6, 3.2 Hz, 1 H, CH₂CO), 2.77 (dd, J = 16.6, 10.4 Hz, 1 H, CH₂CO), 3.76 (dd, J = 10.4, 3.2 Hz, 1 H, CHCO), 4.03 (q, J = 7.2 Hz, 2 H, CH ₂CH₃), 4.10 (q, J = 7.6 Hz, 2 H, CH ₂CH₃), 5.08 (d, J = 12.4 Hz, 1 H, CH₂Ph), 5.12 (s, 2 H, CH₂Ph), 5.14 (d, J = 12.4 Hz, 1 H, CH₂Ph), 7.22–7.25 (m, 4 H, ArH), 7.30–7.32 (m, 6 H, ArH). ¹³C NMR (100 MHz, CDCl₃): δ = 13.9, 14.1, 17.9, 32.9, 45.5, 55.6, 60.8, 61.2, 67.5, 128.1, 128.2, 128.3, 128.3, 128.5, 128.5, 135.1, 169.9, 170.1, 171.5, 171.5 (two carbons overlapped). MS–FAB: m/z = 471 [M + H⁺], 91. HRMS: m/z calcd for C₂₆H₃₁O₈: 471.2019; found: 471.2022.