Synlett 2007(16): 2525-2528  
DOI: 10.1055/s-2007-986647
LETTER
© Georg Thieme Verlag Stuttgart · New York

Synthesis of Marine Oxylipins Constanolactones C and D

Jörg Pietruszka*, Anja C. M. Rieche, Niklas Schöne
Institut für Bioorganische Chemie, Heinrich-Heine-Universität Düsseldorf, Forschungszentrum Jülich, Stetternicher Forst Geb. 15.8, 52428 Jülich, Germany
Fax: +49(2461)616196; e-Mail: j.pietruszka@fz-juelich.de;
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Publikationsverlauf

Received 19 July 2007
Publikationsdatum:
12. September 2007 (online)

Abstract

After providing the marine oxylipins constanolactones A and B, the next two members of this family were synthesized for the first time. Key to the success was a highly enantioselective and Z-selective reagent-controlled allyl addition (>99%) en route to the aliphatic side chain.

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Spectroscopic data of 1c, 1d, 2, 4, 12 and 13:
Aldehyde 2: R f 0.48 (EtOAc); [α]20 D +73.0 (c = 2.4, CHCl3). 1H NMR (600 MHz, CDCl3): δ = 1.15 (ddd, 3 J 3a,1 = 8.4 Hz, 3 J 3a,2 = 6.4 Hz, 2 J 3a,3b = 4.8 Hz, 1 H, 3-Ha), 1.37 (ddd, 3 J 3b,2 = 9.2 Hz, 3 J 3b,1 = 4.8 Hz, 2 J 3b,3a = 4.8 Hz, 1 H, 3-Hb), 1.71 (dddd, 2 J 3 ′a,3 ′b = 13.8 Hz, 3 J 3 ′a,4 ′a = 10.9 Hz, 3 J 3 ′a,2 = 10.6 Hz, 3 J 3 ′a,4 ′b = 4.8 Hz, 1 H, 3′-Ha), 1.79 (dddd, 3 J 2,3b = 9.2 Hz, 3 J 2,2 = 7.2 Hz, 3 J 2,3a = 6.4 Hz, 3 J 2,1 = 4.0 Hz, 1 H, 2-H), 1.85 (ddddd, 3 J 4 ′a,3 ′a = 10.9 Hz, 2 J 4 ′a,4 ′b = 9.9 Hz, 3 J 4 ′a,5 ′a = 9.1 Hz, 3 J 4 ′a,5 ′b = 7.0 Hz, 3 J 4 ′a,3 ′b = 4.7 Hz, 1 H, 4′-Ha), 1.98 (ddddd, 2 J 4 ′b,4 ′a = 9.9 Hz, 3 J 4 ′b,3 ′b = 8.1 Hz, 3 J 4 ′b,5 ′a = 7.1 Hz, 3 J 4 ′b,5 ′b = 4.8 Hz, 3 J 4 ′b,3 ′a = 4.8 Hz, 1 H, 4′-Hb), 2.05 (ddddd, 2 J 3 ′b,3 ′a = 13.8 Hz, 3 J 3 ′b,4 ′b = 8.1 Hz, 3 J 3 ′b,4 ′a = 4.7 Hz, 3 J 3 ′b,2 = 3.4 Hz, 4 J 3 ′b,5 ′b = 1.1 Hz, 1 H, 3′-Hb), 2.11 (dddd, 3 J 1,3a = 8.4 Hz, 3 J 1,3b = 4.8 Hz, 3 J 1,2 = 4.0 Hz, 3 J 1,CHO = 4.0 Hz, 1 H, 1-H), 2.48 (dddd, 2 J 5 ′a,5 ′b = 17.8 Hz, 3 J 5 ′a,4 ′a = 9.1 Hz, 3 J 5 ′a,4 ′b = 7.1 Hz, 4 J 5 ′a,3 = 0.9 Hz, 1 H, 5′-Ha), 2.60 (dddd, 2 J 5 ′b,5 ′a = 17.8 Hz, 3 J 5 ′b,4 ′a = 7.0 Hz, 3 J 5 ′b,4 ′b = 4.8 Hz, 4 J 5 ′b,3 ′b = 1.1 Hz, 1 H, 5′-Hb), 3.90 (ddd, 3 J 2 ′,3 ′a = 10.6 Hz, 3 J 2 ′,2 = 7.2 Hz, 3 J 2 ′,3 ′b = 3.4 Hz, 1 H, 2′-H), 9.38 (d, 3 J CHO,1 = 4.0 Hz, 1 H, CHO). 13C NMR (151 MHz, CDCl3): δ = 11.9 (C-3), 18.4 (C-4′), 26.8 (C-2), 26.9 (C-1), 28.0 (C-3′), 29.5 (C-5′), 80.8 (C-2′), 170.7 (C-6′), 199.8 (CHO). HRMS (ESI, 70 eV): m/z calcd for C9H12O3: 168.0786; found: 168.0790.
Iodide 4: R f 0.19 (PE-EtOAc, 90:10); [α]20 D -25 (c = 0.90, CHCl3). 1H NMR (600 MHz, CDCl3): δ = 0.98 (t, 3 J 11,10 = 7.5 Hz, 3 H, 11-H), 1.81 (d, 3 J OH,3 = 4.3 Hz, 1 H, OH), 2.07 (qddt, 3 J 10,11 = 7.5 Hz, 3 J 10,9 = 7.2 Hz, 4 J 10,8 = 1.6 Hz, 5 J 10,7 = 0.8 Hz, 2 H, 10-H), 2.34 (mc, 2 H, 4-H), 2.80 (ddddtt, 3 J 7,6 = 7.4 Hz, 3 J 7,8 = 7.2 Hz, 4 J 7,9 = 1.7 Hz, 4 J 7,5 = 1.7 Hz, 5 J 7,10 = 0.8 Hz, 5 J 7,4 = 0.8 Hz, 2 H, 7-H), 4.15 (mc, 1 H, 3-H), 5.29 (dtt, 3 J 8,9 = 10.6 Hz, 3 J 8,7 = 7.2 Hz, 4 J 8,10 = 1.6 Hz, 1 H, 8-H), 5.39 (dtt, 3 J 5,6 = 10.8 Hz, 3 J 5,4 = 7.5 Hz, 4 J 5,7 = 1.7 Hz, 1 H, 5-H), 5.42 (dtt, 3 J 9,8 = 10.6 Hz, 3 J 9,10 = 7.2 Hz, 4 J 9,7 = 1.7 Hz, 1 H, 9-H), 5.59 (dtt, 3 J 6,5 = 10.8 Hz, 3 J 6,7 = 7.4 Hz, 4 J 6,4 = 1.6 Hz, 1 H, 6-H), 6.38 (dd, 3 J 1,2 = 14.5 Hz, 4 J 1,3 = 1.4 Hz, 1 H, 1-H), 6.60 (dd, 3 J 2,1 = 14.5 Hz, 3 J 2,3 = 5.9 Hz, 1 H, 2-H). 13C NMR (151 MHz, CDCl3): δ = 14.2 (C-11), 20.6 (C-10), 25.7 (C-7), 34.6 (C-4), 73.8 (C-3), 77.3 (C-1), 123.6 (C-5), 126.5 (C-8), 132.4 (C-9), 132.5 (C-6), 147.7 (C-2). GC-MS (EI, +ve ions): m/z (%) = 274(1) [M - H2O]+, 183 (100) [C3H4IO+].
Constanolactone C (1c): R f 0.22 (EtOAc); separation of the diastereomers 1c and 1d with semi-preparative HPLC (Maxsil 5 µm, 250 × 10 mm; c = 6.4 mg/mL; flow = 3 mL/min; λ = 202 nm); [α]20 D -5.8 (c = 0.70, CHCl3). 1H NMR (600 MHz, CDCl3): δ = 0.62 (ddd, 3 J 7a,8 = 8.6 Hz, 2 J 7a,7b = 5.2 Hz, 3 J 7a,6 = 5.2 Hz, 1 H, 7-Ha), 0.75 (ddd, 3 J 7b,6 = 8.8 Hz, 3 J 7b,8 = 5.6 Hz, 2 J 7b,7a = 5.2 Hz, 1 H, 7-Hb), 0.97 (t, 3 J 20,19 = 7.5 Hz, 3 H, 20-H), 1.00 (dddd, 3 J 6,7b = 8.8 Hz, 3 J 6,5 = 8.4 Hz, 3 J 6,7a = 5.2 Hz, 3 J 6,8 = 4.4 Hz, 1 H, 6-H), 1.15 (dddd, 3 J 8,7a = 8.6 Hz, 3 J 8,9 = 7.4 Hz, 3 J 8,7b = 5.6 Hz, 3 J 8,6 = 4.4 Hz, 1 H, 8-H), 1.67 (dddd, 2 J 4a,4b = 13.9 Hz, 3 J 4a,3a = 10.6 Hz, 3 J 4a,5 = 10.1 Hz, 3 J 4a,3b = 4.9 Hz, 1 H, 4-Ha) 1.80 (ddddd, 2 J 3a,3b = 13.6 Hz, 3 J 3a,4a = 10.6 Hz, 3 J 3a,2a = 8.7 Hz, 3 J 3a,2b = 7.1 Hz, 3 J 3a,4b = 4.8 Hz, 1 H, 3-Ha), 1.74 (br, 2 H, OH), 1.95 (ddddd, 2 J 3b,3a = 13.6 Hz, 3 J 3b,2a = 7.0 Hz, 3 J 3b,2b = 5.3 Hz, 3 J 3b,4b = 5.1 Hz, 3 J 3b,4a = 4.9 Hz, 1 H, 3-Hb), 2.01 (ddddd, 2 J 4b,4a = 13.9 Hz, 3 J 4b,3b = 5.1 Hz, 3 J 4b,3a = 4.8 Hz, 3 J 4b,5 = 3.5 Hz, 5 J 4b,2b = 1.1 Hz, 1 H, 4-Hb), 2.07 (qddt, 3 J 19,20 = 7.5 Hz, 3 J 19,18 = 7.2 Hz, 4 J 19,17 = 1.6 Hz, 5 J 19,16 = 0.8 Hz, 2 H, 19-H), 2.33 (ddddt, 2 J 13a,13b = 14.4 Hz, 3 J 13a,14 = 7.1 Hz, 3 J 13a,12 = 5.9 Hz, 4 J 13a,15 = 1.6 Hz, 5 J 13a,16 = 0.8 Hz, 1 H, 13-Ha), 2.38 (ddddt, 2 J 13b,13a = 14.4 Hz, 3 J 13b,14 = 7.5 Hz, 3 J 13b,12 = 6.9 Hz, 4 J 13b,15 = 1.5 Hz, 5 J 13b,16 = 0.8 Hz, 1 H, 13-Hb), 2.45 (ddd, 2 J 2a,2b = 17.8 Hz, 3 J 2a,3a = 8.7 Hz, 3 J 2a,3b = 7.0 Hz, 1 H, 2-Ha), 2.56 (dddd, 2 J 2b,2a = 17.8 Hz, 3 J 2b,3a = 7.1 Hz, 3 J 2b,3b = 5.3 Hz, 5 J 2b,4b = 1.1 Hz, 1 H, 2-Hb), 2.81 (ddddtdd, 3 J 16,15 = 7.3 Hz, 3 J 16,17 = 7.3 Hz, 4 J 16,18 = 1.6 Hz, 4 J 16,14 = 1.6 Hz, 5 J 16,19 = 0.8 Hz, 5 J 16,13a = 0.8 Hz, 5 J 16,13b = 0.8 Hz, 2 H, 16-H), 3.70-3.74 (m, 1 H, 9-H), 3.72 (ddd, 3 J 5,4a = 10.1 Hz, 3 J 5,6 = 8.4 Hz, 3 J 5,4b = 3.5 Hz, 1 H, 5-H), 4.20 (mc, 1 H, 12-H), 5.30 (dtt, 3 J 17,18 = 10.6 Hz, 3 J 17,16 = 7.2 Hz, 4 J 17,19 = 1.6 Hz, 1 H, 17-H), 5.40 (dtt, 3 J 18,17 = 10.6 Hz, 3 J 18,19 = 7.2 Hz, 4 J 18,16 = 1.6 Hz, 1 H, 18-H), 5.43 (dtt, 3 J 14,15 = 10.7 Hz, 3 J 14,13 = 7.3 Hz, 4 J 14,16 = 1.6 Hz, 1 H, 14-H), 5.53 (dtdd, 3 J 15,14 = 10.7 Hz, 3 J 15,16 = 7.3 Hz, 4 J 15,13a = 1.6 Hz, 4 J 15,13b = 1.5 Hz, 1 H, 15-H), 5.79 (mc, 2 H, 10-H, 11-H). 13C NMR (151 MHz, CDCl3): δ = 7.5 (C-7), 14.2 (C-20), 18.3 (C-3), 20.4 (C-6), 20.6 (C-19), 23.4 (C-8), 25.7 (C-16), 27.8 (C-4), 29.5 (C-2), 35.0 (C-13), 71.6 (C-12), 74.2 (C-9), 83.6 (C-5), 124.8 (C-14), 126.9 (C-17), 131.3 (C-15), 132.0 (C-10), 132.2 (C-18), 133.6 (C-11), 171.5 (C-1). HRMS (ESI, +ve ions, solution in MeOH): m/z calcd for C20H30NaO4: 357.2036; found: 357.2024.
Constanolactone D (1d): R f 0.22 (EtOAc); [α]20 D -9.1 (c = 0.60, CHCl3). 1H NMR (600 MHz, CDCl3): δ = 0.59 (ddd, 3 J 7a,8 = 8.8 Hz, 3 J 7a,6 = 5.3 Hz, 2 J 7a,7b = 5.3 Hz, 1 H, 7-Ha), 0.64 (ddd, 3 J 7b,6 = 8.7 Hz, 3 J 7b,8 = 5.5 Hz, 2 J 7b,7a = 5.3 Hz, 1 H, 7-Hb), 0.97 (t, 3 J 20,19 = 7.5 Hz, 3 H, 20-H), 1.11 (dddd, 3 J 6,7b = 8.7 Hz, 3 J 6,5 = 8.1 Hz, 3 J 6,7a = 5.3 Hz, 3 J 6,8 = 4.4 Hz, 1 H, 6-H), 1.14 (dddd, 3 J 8,7a = 8.8 Hz, 3 J 8,9 = 7.3 Hz, 3 J 8,7b = 5.5 Hz, 3 J 8,6 = 4.4 Hz, 1 H, 8-H), 1.69 (dddd, 2 J 4a,4b = 13.9 Hz, 3 J 4a,3a = 10.9 Hz, 3 J 4a,5 = 10.5 Hz, 3 J 4a,3b = 5.1 Hz, 1 H, 4-Ha), 1.81 (ddddd, 2 J 3a,3b = 13.6 Hz, 3 J 3a,4a = 10.9 Hz, 3 J 3a,2a = 8.8 Hz, 3 J 3a,2b = 7.1 Hz, 3 J 3a,4b = 5.0 Hz, 1 H, 3-Ha), 1.87 (br, 2 H, OH), 1.96 (ddddd, 2 J 3b,3a = 13.6 Hz, 3 J 3b,2a = 7.1 Hz, 3 J 3b,2b = 5.2 Hz, 3 J 3b,4a = 5.1 Hz, 3 J 3b,4b = 4.8 Hz, 1 H, 3-Hb), 2.02 (ddddd, 2 J 4b,4a = 13.9 Hz, 3 J 4b,3a = 5.0 Hz, 3 J 4b,3b = 4.8 Hz, 3 J 4b,5 = 3.3 Hz, 5 J 4b,2b = 1.2 Hz, 1 H, 4-Hb), 2.07 (qddt, 3 J 19,20 = 7.5 Hz, 3 J 19,18 = 7.3 Hz, 4 J 19,17 = 1.6 Hz, 5 J 19,16 = 0.7 Hz, 2 H, 19-H), 2.33 (ddddt, 2 J 13a,13b = 14.3 Hz, 3 J 13a,14 = 7.1 Hz, 3 J 13a,12 = 5.7 Hz, 4 J 13a,15 = 1.6 Hz, 5 J 13a,16 = 0.7 Hz, 1 H, 13-Ha), 2.38 (ddddt, 2 J 13b,13a = 14.3 Hz, 3 J 13b,12 = 7.6 Hz, 3 J 13b,14 = 7.1 Hz, 4 J 13b,15 = 1.6 Hz, 5 J 13b,16 = 0.5 Hz, 1 H, 13-Hb), 2.46 (ddd, 2 J 2a,2b = 17.7 Hz, 3 J 2a,3a = 8.8 Hz, 3 J 2a,3b = 7.1 Hz, 1 H, 2-Ha), 2.57 (dddd, 2 J 2b,2a = 17.7 Hz, 3 J 2b,3a = 7.1 Hz, 3 J 2b,3b = 5.2 Hz, 5 J 2b,4b = 1.2 Hz, 1 H, 2-Hb), 2.81 (ddddtdd, 3 J 16,15 = 7.4 Hz, 3 J 16,17 = 7.2 Hz, 4 J 16,14 = 1.7 Hz, 4 J 16,18 = 1.6 Hz, 5 J 16,19 = 0.7 Hz, 5 J 16,13a = 0.7 Hz, 5 J 16,13b = 0.5 Hz, 2 H, 16-H), 3.71 (mc, 1 H, 9-H), 3.73 (ddd, 3 J 5,4a = 10.5 Hz, 3 J 5,6 = 8.1 Hz, 3 J 5,4b = 3.3 Hz, 1 H, 5-H), 4.19 (mc, 1 H, 12-H), 5.30 (dtt, 3 J 17,18 = 10.6 Hz, 3 J 17,16 = 7.2 Hz, 4 J 17,19 = 1.6 Hz, 1 H, 17-H), 5.40 (dtt, 3 J 18,17 = 10.6 Hz, 3 J 18,19 = 7.3 Hz, 4 J 18,16 = 1.6 Hz, 1 H, 18-H), 5.42 (dddt, 3 J 14,15 = 10.8 Hz, 3 J 14,13b = 7.3 Hz, 3 J 14,13a = 7.1 Hz, 4 J 14,16 = 1.7 Hz, 1 H, 14-H), 5.55 (dtt, 3 J 15,14 = 10.8 Hz, 3 J 15,16 = 7.4 Hz, 4 J 15,13 = 1.6 Hz, 1 H, 15-H), 5.79 (mc, 2 H, 10-H, 11-H). 13C NMR (151 MHz, CDCl3): δ = 6.6 (C-7), 14.2 (C-20), 18.4 (C-3), 20.6 (C-19), 21.2 (C-8), 23.4 (C-6), 25.7 (C-16), 27.9 (C-4), 29.5 (C-2), 35.2 (C-13), 71.5 (C-12), 73.8 (C-9), 83.3 (C-5), 124.7 (C-14), 126.8 (C-17), 131.6 (C-15), 131.7 (C-10), 132.2 (C-18), 133.2 (C-11), 171.5 (C-1). HRMS (ESI, +ve ions, solution in MeOH): m/z calcd for C20H30NaO4: 357.2036; found: 357.2024.
Acetate 12: R f 0.34 (PE-EtOAc, 50:50); [α]20 D -7.5 (c = 0.70, CHCl3). 1H NMR (600 MHz, CDCl3): δ = 0.63 (ddd, 3 J 7a,8 = 8.6 Hz, 3 J 7a,6 = 5.3 Hz, 2 J 7a,7b = 5.3 Hz, 1 H, 7-Ha), 0.74 (ddd, 3 J 7b,6 = 8.9 Hz, 3 J 7b,8 = 5.5 Hz, 2 J 7b,7a = 5.3 Hz, 1 H, 7-Hb), 0.97 (t, 3 J 20,19 = 7.5 Hz, 3 H, 20-H), 1.04 (dddd, 3 J 6,7b = 8.9 Hz, 3 J 6,5 = 7.5 Hz, 3 J 6,7a = 5.3 Hz, 3 J 6,8 = 4.4 Hz, 1 H, 6-H), 1.23 (dddd, 3 J 8,7a = 8.6 Hz, 3 J 8,9 = 8.1 Hz, 3 J 8,7b = 5.5 Hz, 3 J 8,6 = 4.4 Hz, 1 H, 8-H), 1.64 (dddd, 2 J 4a,4b = 14.0 Hz, 3 J 4a,3a = 11.0 Hz, 3 J 4a,5 = 10.6 Hz, 3 J 4a,3b = 5.2 Hz, 1 H, 4-Ha), 1.81 (ddddd, 2 J 3a,3b = 13.8 Hz, 3 J 3a,4a = 11.0 Hz, 3 J 3a,2a = 8.9 Hz, 3 J 3a,2b = 7.1 Hz, 3 J 3a,4b = 5.1 Hz, 1 H, 3-Ha), 1.93 (ddddd, 2 J 3b,3a = 13.8 Hz, 3 J 3b,2a = 7.1 Hz, 3 J 3b,4a = 5.2 Hz, 3 J 3b,2b = 5.1 Hz, 3 J 3b,4b = 4.5 Hz, 1 H, 3-Hb), 1.98 (ddddd, 2 J 4b,4a = 14.0 Hz, 3 J 4b,3a = 5.1 Hz, 3 J 4b,3b = 4.5 Hz, 3 J 4b,5 = 3.2 Hz, 4 J 4b,2b = 1.1 Hz, 1 H, 4-Hb), 2.07 (qddt, 3 J 19,20 = 7.5 Hz, 3 J 19,18 = 7.2 Hz, 4 J 19,17 = 1.6 Hz, 5 J 19,16 = 0.8 Hz, 2 H, 19-H), 2.07, 2.08 (2 × s, 6 H, 9-OAc, 12-OAc), 2.39 (ddddt, 2 J 13a,13b = 14.6 Hz, 3 J 13a,14 = 7.1 Hz, 3 J 13a,12 = 6.3 Hz, 4 J 13a,15 = 1.6 Hz, 6 J 13a,16 = 0.8 Hz, 1 H, 13-Ha), 2.45 (ddd, 2 J 2a,2b = 17.7 Hz, 3 J 2a,3a = 8.9 Hz, 3 J 2a,3b = 7.1 Hz, 1 H, 2-Ha), 2.46 (ddddt, 2 J 13b,13a = 14.6 Hz, 3 J 13b,14 = 7.6 Hz, 3 J 13b,12 = 6.8 Hz, 4 J 13b,15 = 1.6 Hz, 5 J 13b,16 = 0.8 Hz, 1 H, 13-Hb), 2.56 (dddd, 2 J 2b,2a = 17.7 Hz, 3 J 2b,3a = 7.1 Hz, 3 J 2b,3b = 5.1 Hz, 4 J 2b,4b = 1.1 Hz, 1 H, 2-Hb), 2.78 (ddddddd, 3 J 16,15 = 7.4 Hz, 3 J 16,17 = 7.3 Hz, 4 J 16,14 = 1.7 Hz, 4 J 16,18 = 1.6 Hz, 5 J 16,13a = 0.8 Hz, 5 J 16,13b = 0.8 Hz, 5 J 16,19a = 0.8 Hz, 2 H, 16-H), 3.80 (ddd, 3 J 5,4a = 10.6 Hz, 3 J 5,6 = 7.5 Hz, 3 J 5,4b = 3.2 Hz, 1 H, 5-H), 4.91 (dddd, 3 J 9,8 = 8.1 Hz, 3 J 9,10 = 5.8 Hz, 4 J 9,11 = 1.3 Hz, 5 J 9,12 = 0.7 Hz, 1 H, 9-H), 5.28 (dtt, 3 J 17,18 = 10.6 Hz, 3 J 17,16 = 7.3 Hz, 4 J 17,19 = 1.6 Hz, 1 H, 17-H), 5.30 (ddddd, 3 J 12,13b = 6.8 Hz, 3 J 12,13a = 6.3 Hz, 3 J 12,11 = 6.2 Hz, 4 J 12,10 = 1.2 Hz, 5 J 12,9 = 0.7 Hz, 1 H, 12-H), 5.34 (dddt, 3 J 14,15 = 10.7 Hz, 3 J 14,13b = 7.6 Hz, 3 J 14,134 = 7.1 Hz, 4 J 14,16 = 1.7 Hz, 1 H, 14-H), 5.39 (dtt, 3 J 18,17 = 10.6 Hz, 3 J 18,19 = 7.2 Hz, 4 J 18,16 = 1.6 Hz, 1 H, 18-H), 5.48 (dtt, 3 J 15,14 = 10.7 Hz, 3 J 15,16 = 7.4 Hz, 4 J 15,13 = 1.6 Hz, 1 H, 15-H), 5.70 (ddd, 3 J 10,11 = 15.7 Hz, 3 J 10,9 = 5.8 Hz, 4 J 10,12 = 1.2 Hz, 1 H, 10-H), 5.82 (ddd, 3 J 11,10 = 15.7 Hz, 3 J 11,12 = 6.2 Hz, 4 J 11,9 = 1.3 Hz, 1 H, 11-H). 13C NMR (151 MHz, CDCl3): δ = 7.6 (C-7), 14.2 (C-20), 18.4 (C-3), 20.1 (C-8), 20.5 (C-19), 20.8 (C-6), 21.2, 21.3 (9-OAc, 12-OAc), 25.6 (C-16), 27.9 (C-4), 29.5 (C-2), 32.2 (C-13), 73.0 (C-12), 75.3 (C-9), 82.3 (C-5), 123.8 (C-14), 126.8 (C-17), 129.1 (C-10), 130.9 (C-11), 131.3 (C-15), 132.2 (C-18), 170.3, 170.3 (9-OAc, 12-OAc), 171.0 (C-1). HRMS (ESI, +ve ions, solution in MeOH): m/z calcd for C24H34NaO6: 441.2248; found: 441.2242.
Acetate 13: R f 0.34 (PE-EtOAc, 50:50); [α]20 D -4.4 (c = 0.50, CHCl3). 1H NMR (600 MHz, CDCl3): δ = 0.59 (ddd, 3 J 7a,8 = 8.6 Hz, 3 J 7a,6 = 5.7 Hz, 2 J 7a,7b = 5.4 Hz, 1 H, 7-Ha), 0.68 (ddd, 3 J 7b,6 = 8.7 Hz, 3 J 7b,8 = 5.4 Hz, 2 J 7b,7a = 5.4 Hz, 1 H, 7-Hb), 0.98 (t, 3 J 20,19 = 7.5 Hz, 3 H, 20-H), 1.17-1.23 (m, 2 H, 6-H, 8-H), 1.64 (dddd, 2 J 4a,4b = 13.7 Hz, 3 J 4a,3a = 10.6 Hz, 3 J 4a,5 = 10.1 Hz, 3 J 4a,3b = 5.0 Hz, 1 H, 4-Ha), 1.81 (ddddd, 2 J 3a,3b = 13.6 Hz, 3 J 3a,4a = 10.6 Hz, 3 J 3a,2a = 8.7 Hz, 3 J 3a,2b = 7.1 Hz, 3 J 3a,4b = 4.9 Hz, 1 H, 3-Ha), 1.94 (ddddd, 2 J 3b,3a = 13.6 Hz, 3 J 3b,2a = 7.0 Hz, 3 J 3b,2b = 5.3 Hz, 3 J 3b,4b = 5.1 Hz, 3 J 3b,4a = 5.0 Hz, 1 H, 3-Hb), 1.97 (ddddd, 2 J 4b,4a = 13.7 Hz, 3 J 4b,3b = 5.1 Hz, 3 J 4b,3a = 4.9 Hz, 3 J 4b,5 = 3.3 Hz, 4 J 4b,2b = 1.2 Hz, 1 H, 4-Hb), 2.07 (qddt, 3 J 19,20 = 7.5 Hz, 3 J 19,18 = 7.2 Hz, 4 J 19,17 = 1.6 Hz, 5 J 19,16 = 0.8 Hz, 2 H, 19-H), 2.07, 2.09 (2 × s, 6 H, 9-OAc, 12-OAc), 2.36 (ddddt, 2 J 13a,13b = 14.6 Hz, 3 J 13a,14 = 7.1 Hz, 3 J 13a,12 = 6.3 Hz, 4 J 13a,15 = 1.5 Hz, 6 J 13a,16 = 0.8 Hz, 1 H, 13-Ha), 2.45 (ddd, 2 J 2a,2b = 17.7 Hz, 3 J 2a,3a = 8.7 Hz, 3 J 2a,3b = 7.0 Hz, 1 H, 2-Ha), 2.45 (ddddt, 2 J 13b,13a = 14.6 Hz, 3 J 13b,14 = 7.5 Hz, 3 J 13b,12 = 6.8 Hz, 4 J 13b,15 = 1.6 Hz, 5 J 13b,16 = 0.8 Hz, 1 H, 13-Hb), 2.55 (dddd, 2 J 2b,2a = 17.7 Hz, 3 J 2b,3a = 7.1 Hz, 3 J 2b,3b = 5.3 Hz, 4 J 2b,4b = 1.2 Hz, 1 H, 2-Hb), 2.78 (ddddddt, 3 J 16,15 = 7.3 Hz, 3 J 16,17 = 7.2 Hz, 4 J 16,14 = 1.7 Hz, 4 J 16,18 = 1.7 Hz, 5 J 16,13a = 0.8 Hz, 5 J 16,13b = 0.8 Hz, 5 J 16,19 = 0.8 Hz, 2 H, 16-H), 3.82 (ddd, 3 J 5,4a = 10.1 Hz, 3 J 5,6 = 6.8 Hz, 3 J 5,4b = 3.3 Hz, 1 H, 5-H), 4.83-4.87 (m, 1 H, 9-H), 5.28 (dtt, 3 J 17,18 = 10.6 Hz, 3 J 17,16 = 7.2 Hz, 4 J 17,19 = 1.6 Hz, 1 H, 17-H), 5.28 (mc, 1 H, 12-H), 5.32 (dtt, 3 J 14,15 = 10.7 Hz, 3 J 14,13 = 7.3 Hz, 4 J 14,16 = 1.7 Hz, 1 H, 14-H), 5.40 (dtt, 3 J 18,17 = 10.6 Hz, 3 J 18,19 = 7.2 Hz, 4 J 18,16 = 1.7 Hz, 1 H, 18-H), 5.49 (dtt, 3 J 15,14 = 10.7 Hz, 3 J 15,16 = 7.3 Hz, 4 J 15,13 = 1.6 Hz, 1 H, 15-H), 5.68-5.74 (m, 2 H, 10-H, 11-H). 13C NMR (151 MHz, CDCl3): δ = 6.7 (C-7), 14.2 (C-20), 18.3 (C-3), 20.3 (C-6, C-8), 20.6 (C-19), 21.2, 21.3 (9-OAc, 12-OAc), 21.7 (C-6, C-8), 25.7 (C-16), 27.8 (C-4), 29.5 (C-2), 32.3 (C-13), 73.0 (C-12), 75.5 (C-9), 81.9 (C-5), 123.7 (C-14), 126.7 (C-17), 129.5 (C-10, C-11), 130.5 (C-11, C-10), 131.4 (C-15), 132.2 (C-18), 170.1, 170.5 (9-OAc, 12-OAc), 171.1 (C-1). HRMS (ESI, +ve ions, solution in MeOH): m/z calcd C24H34NaO6: 441.2248; found: 441.2253.