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Synthesis 2008(15): 2323-2326  
DOI: 10.1055/s-2008-1067175
SHORTPAPER
© Georg Thieme Verlag Stuttgart ˙ New York

A Concise Enantioselective Strategy to (+)-(R)-Goniothalamin and (+)-(R)-Goniothalamin Oxide by Employing Hydrolytic Kinetic Resolution and Ring-Closing Metathesis as Key Steps

D. Subhas Bose*, A. V. Narsimha Reddy, Bingi Srikanth
Organic Chemistry Division III, Fine Chemicals Laboratory, Indian Institute of Chemical Technology, Hyderabad 500007, India
Fax: +91(40)27160387; e-Mail: dsb@iict.res.in; e-Mail: bose_iict@yahoo.co.in;
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Publication History

Received 10 April 2008
Publication Date:
08 July 2008 (online)

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Abstract

An efficient and general strategy to (R)-goniothalamin and (R)-goniothalamin oxide is described by using Jacobsen’s hydrolytic­ kinetic resolution of racemic epoxide and ring-closing metathesis (RCM) as key steps, which provided a rapid access to these natural products that display a fascinating array of biological activity. (R)-Goniothalamin oxide was prepared in high yield and diastereomeric excess under various epoxidation conditions.

Key words

Jacobsen’s epoxidation - goniothalamin - styryl lactones - metathesis - natural products

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(+)-(R)-Goniothalamin (1): White crystalline solid; mp 82-83 ˚C (Lit. [¹6l] 81-82 ˚C). [α]D +169.4 (c 1.45, CHCl3) [Lit. [6] [α]D +170.3 (c 1.38, CHCl3)]. IR (KBr): 3050, 3025, 2931, 1722, 1610, 1245, 810, 700 cm-¹. ¹H NMR (300 MHz, CDCl3): δ = 2.55 (m, 2 H), 5.12 (dq, J 5,6 = 6.5 Hz, J 5,4 = 1.2 Hz, 1 H), 6.11 (dt, J 2,3 = 9.7 Hz, J 2,4 = 1.7 Hz, 1 H), 6.29 (dd, J 6,7 = 16.1 Hz, J 6,5 = 6.5 Hz, 1 H), 6.74 (d, J 7,6 = 15.6 Hz, 1 H), 6.94 (dt, J 3,2 = 9.7 Hz, J 3,4 = 4.4 Hz, 1 H), 7.30-7.42 (m, 5 H). ¹³C NMR (75 MHz, CDCl3): δ = 30.1, 77.9, 121.8, 125.5, 126.7, 128.4, 133.3, 135.2, 144.8, 164.1. MS (APCI): m/z (%): 201.0 (39) [M+ + H], 183.1 (100), 155.2 (66), 130.1 (41).

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(+)-(R)-Goniothalamin Oxide (2): Mp 90-92 ˚C (Lit. [²5b] 90-94 ˚C). [α]D +100.1 (c 0.88, CHCl3) [Lit.²5b [α]D +100.7 (c 0.70, CHCl3)]. IR (KBr): 3055, 3025, 2928, 1720, 1605, 1245, 1035, 808 cm-¹. ¹H NMR (300 MHz, CDCl3): δ = 2.59 (m, 2 H), 3.28 (dd, J 6,5 = 5.6 Hz, J 6,7 = 2.0 Hz, 1 H), 3.91 (d, J 7,6 = 1.8 Hz, 1 H), 4.45 (dt, J 5,4 = 9.4 Hz, J 5,4 ¢ and 6 = 5.5 Hz, 1 H), 6.07 (dt, J 2,3 = 9.7 Hz, J 2,4 = 2.0 Hz, 1 H), 6.95 (m, 1 H), 7.32-7.39 (m, 5 H). ¹³C NMR (75 MHz, CDCl3): δ = 26.3, 57.5, 61.9, 77.2, 121.6, 125.5, 128.7, 135.5, 144.4, 164.0. MS (APCI): m/z (%) = 217.0 (100) [M+ + H], 199.0 (45), 171.1 (83), 143.1 (45), 139.0 (32), 105. 0 (31), 91.0 (31). HRMS: m/z [M + Na+] calcd for C13H12NaO3: 239.0684; found: 239.0682.