Supporting Information
Enantioselective reduction of prochiral ketones with NaBH4/Me2SO4/(S)-Me-CBS Yuhan Zhou*, Guchao Gao, Yuming Song, Jingping Qu* (State Key Laboratory of Fine Chemicals, School of Pharmaceutical Science and Technology, Dalian University of Technology, Dalian 116024, P.R. China) Address correspondence to Yuhan Zhou and Jingping Qu, School of Pharmaceutical Science and Technology, Dalian University of Technology, Dalian 116024, P. R. China. Email:
[email protected] (Y. Zhou);
[email protected] (J. Qu).
Contents
Spectroscopic and characterization data of the alcohols
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1
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H NMR spectra of the alcohols
HPLC chromatograms of the racemic and chiral alcohols
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Spectroscopic and characterization data of the alcohols 1-Phenylethanol:[1] Colorless liquid, yield 99%, 96% ee. The enantiomeric excess was determined by HPLC with a chiral column (Daicel OD; eluent: n-hexane/2-propanol = 95/5; flow rate: 0.5 mL/min; UV detector: 254 nm). 1H NMR (400 MHz, CDCl3): δ 7.37-7.24 (m, 5H, PhH), 4.87 (q, J = 6.4 Hz, 1H, CH), 2.08 (s, 1H, OH), 1.48 (d, J = 6.4 Hz, 3H, CH3). 1-Phenylpropan-1-ol:[2] Colorless liquid, yield 99%, 98% ee. The enantiomeric excess was determined by HPLC with a chiral column (Daicel OD; eluent: n-hexane/2-propanol = 98/2; flow rate: 0.5 mL/min; UV detector: 254 nm). 1H NMR (400 MHz, CDCl3) δ: 7.37-7.25 (m, 5H, Ph-H), 4.58 (t, J = 6.4 Hz, 1H, CH), 2.15 (s, 1H, OH), 1.86-1.71 (m, 2H, CH2), 0.91 (t, J = 7.2 Hz, 3H, CH3). 2-Chloro-1-phenylethanol:[1] Colorless liquid, yield 97%, 96% ee. The enantiomeric excess was determined by HPLC with a chiral column (Daicel OD; eluent: n-hexane/2-propanol = 98/2; flow rate: 0.6 mL/min; UV detector: 254 nm). 1H NMR (400 MHz, CDCl3) δ: 7.39-7.31 (m, 5H, PhH), 4.90 (m, 1H, CH), 3.77-3.62 (m, 2H, CH2), 2.65 (d, J = 2.8 Hz, 1H, OH). 2-Bromo-1-phenylethanol:[1] Colorless liquid, yield 98%, 95% ee. The enantiomeric excess was determined by HPLC with a chiral column (Daicel OD; eluent: n-hexane/2-propanol = 98/2; flow rate: 0.6 mL/min; UV detector: 254 nm). 1H NMR (400 MHz, CDCl3) δ: 7.39-7.30 (m, 5H, PhH), 4.93 (m, 1H, CH), 3.67-3.52 (m, 2H, CH2), 2.62 (m, 1H, OH). 1-(4-Chlorophenyl)ethanol:[3] Colorless liquid, yield 90%, 97% ee. The enantiomeric excess was determined by HPLC with a chiral column (Daicel OD; eluent: n-hexane/2-propanol = 99/1; flow rate: 0.5 mL/min; UV detector: 254 nm). 1H NMR (400 MHz, CDCl3) δ: 7.31 (m, 4H, PhH), 4.88 (m, 1H, CH), 1.91 (s, 1H, OH), 1.47 (d,J = 6.4 Hz, 3H, CH3). 1-(4-Bromophenyl)ethanol:[3] Colorless liquid, yield 80%, 97% ee. The enantiomeric excess was determined by HPLC with a chiral column (Daicel OD; eluent: n-hexane/2-propanol = 99/1; flow rate: 0.5 mL/min; UV detector: 254 nm). 1H NMR (400 MHz, CDCl3) δ: 7.47 (d, 2H, J = 8.4 Hz, PhH), 7.25 (d, 2H, J = 8.4 Hz, PhH), 4.86 (q, J = 6.4 Hz, 1H, CH), 1.85 (s, 1H, OH), 1.47 (d, J = 6.4 Hz, 3H, CH3). 1-(Naphthalen-2-yl)ethanol:[1] Colorless liquid, yield 94%, 99% ee. The enantiomeric excess was determined by HPLC with a chiral column (Daicel OD; eluent: n-hexane/2-propanol = 98/2; flow rate: 0.6 mL/min; UV detector: 254 nm). 1H NMR (400 MHz, CDCl3) δ: 7.81-7.22 (m, 7H, Ar-H), 5.02 (q, J = 6.4 Hz, 1H, CH), 2.10 (s, 1H, OH), 1.55 (d, J = 6.4 Hz, 3H, CH3).
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3-Chloro-1-phenylpropan-1-ol:[4] Colorless liquid, yield 95%, 93% ee. The enantiomeric excess was determined by HPLC with a chiral column (Daicel OD; eluent: n-hexane/2-propanol = 97/3; flow rate: 0.5 mL/min; UV detector: 254 nm). 1H NMR (400 MHz, CDCl3) δ: 7.37-7.28 (m, 5H, PhH), 4.94 (m, 1H, CH), 3.77-3.53 (m, 2H, CH2-Cl), 2.28-2.01 (m, 2H, CH2), 2.00 (s, 1H, OH).
REFERENCES 1. Xiao, J.; Wong, Z. Z.; Lu, Y. P.; Loh, T. P. Adv. Synth. Catal. 2010, 352, 1107-1112. 2. Wu, X.-F.; Min, C.; Nyamzundui, E.; Zhou, H.-B.; Dong, C. Tetrahedron: Asymmetry 2011, 22, 1640-1643. 3. Stepanenko, V.; Jesús, M. D.; Correa, W.; Guzmán, I.; Vázquez, C.; Cruz, W.; Ortiz-Marciales, M.; Barnes, C. L. Tetrahedron Lett. 2007, 48, 5799-5802. 4. Mahale, R. D.; Chaskar, S. P.; Patil, K. E.; Maikap, G. C.; Gurjar, M. K. Org. Process. Res. Dev. 2012, 16, 710-713.
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1
H NMR spectra of the alcohols
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OH Et
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HPLC chromatograms of the racemic and chiral alcohols 1-Phenylethanol
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1-Phenylpropan-1-ol
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2-Chloro-1-phenylethanol
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2-Bromo-1-phenylethanol
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1-(4-Chlorophenyl)ethanol
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1-(4-Bromophenyl)ethanol
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1-(Naphthalen-2-yl)ethanol
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3-Chloro-1-phenylpropan-1-ol
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