Synlett 2007(18): 2894-2896  
DOI: 10.1055/s-2007-991056
LETTER
© Georg Thieme Verlag Stuttgart · New York

A Concise Synthesis of (-)-Deoxoprosopinine

Satyendra Kumar Pandey, Pradeep Kumar*
Division of Organic Chemistry: Technology, National Chemical Laboratory, Pune 411008, India
Fax: +91(20)25902629; e-Mail: pk.tripathi@ncl.res.in;
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Publikationsverlauf

Received 13 July 2007
Publikationsdatum:
25. September 2007 (online)

Abstract

A simple and highly efficient approach to (-)-deoxo­prosopinine from racemic epoxide as a starting material is described employing a Jacobsen’s hydrolytic kinetic resolution (HKR) and Sharpless asymmetric dihydroxylation (AD) as key steps.

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The diastereoselectivity was determined from 1H NMR and 13C NMR spectral data. Spectral data of compound 11: mp 137 °C; [α]D 25 +6.90 (c 1.00, CHCl3). IR (CHCl3): ν = 3434, 3018, 2927, 1719, 1508, 1216 cm-1. 1H NMR (200 MHz, CDCl3): δ = 0.89 (t, J = 5.95 Hz, 3 H), 1.26-1.70 (m, 29 H), 2.27 (br s, 2 H), 3.62-3.71 (m, 1 H), 3.91 (d, J = 6.45 Hz, 1 H), 4.06 (d, J = 1.61 Hz, 1 H), 4.29 (q, J = 6.72, 13.70 Hz, 2 H), 4.55 (d, J = 8.87 Hz, 1 H), 5.10 (s, 2 H), 7.32-7.38 (m, 5 H) ppm. 13C NMR (50 MHz, CDCl3): δ = 14.0, 22.6, 25.8, 29.2, 29.6, 29.8, 31.4, 31.8, 35.5, 51.1, 61.8, 66.4, 72.3, 73.4, 127.9, 128.4, 136.5, 156.2, 173.4 ppm. ESI-MS: m/z = 516 [M + Na]+. Anal. Calcd (%) for C28H47NO6: C, 68.12; H, 9.60; N, 2.84. Found: C, 68.17; H, 9.58; N, 2.82.

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Spectral data of compound 13: mp 96 °C; [α]D 25 +5.65 (c 0.60, CHCl3). IR (CHCl3): ν = 3583, 3436, 3019, 2928, 1725, 1519, 1455, 1215 cm-1. 1H NMR (200 MHz, CDCl3): δ = 0.88 (t, J = 6.07 Hz, 3 H), 1.26-1.79 (m, 30 H), 2.11 (br s, 1 H), 2.65-2.74 (m, 1 H), 3.58 (d, J = 4.06 Hz, 1 H), 4.11-4.17 (m, 1 H) 4.21 (q, J = 7.12, 13.86 Hz, 2 H) ppm. 13C NMR (50 MHz, CDCl3): δ = 14.0, 14.2, 22.6, 26.1, 28.0, 29.3, 29.5, 29.6, 31.8, 35.8, 51.6, 60.8, 61.5, 65.5, 172.2 ppm. ESI-MS: m/z = 342 [M + H]+. Anal. Calcd (%) for C20H39NO3: C, 70.33; H, 11.51; N, 4.10. Found: C, 70.35; H, 11.48; N, 4.12.