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Synlett 2009(13): 2129-2132  
DOI: 10.1055/s-0029-1217556
LETTER
© Georg Thieme Verlag Stuttgart ˙ New York

Stereoselective Total Synthesis of Stagonolide C and Formal Total Synthesis of Modiolide A

Debendra K. Mohapatra*, Uttam Dash, P. Ramesh Naidu, J. S. Yadav*
Organic Chemistry Division-I, Indian Institute of Chemical Technology (CSIR), Uppal Road, Hyderabad 500007, India
Fax: +91(40)27160512; e-Mail: mohapatra@iict.res.in;
Further Information

Publication History

Received 6 May 2009
Publication Date:
15 July 2009 (online)

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Abstract

The influence of protecting groups at C4 and C7 on a ring-closing metathesis reaction was investigated. Matched induction led to the total synthesis of stagonolide C and the formal total synthesis of modiolide A.

Key words

decanolide - stagonolide C - modiolide A - ring-closing metathesis - Sharpless asymmetric epoxidation

11

Analytical and spectral data of 17: [α]D ²7 -30.4 (c 1.8, CHCl3); IR (KBr): 3456, 2922, 2853, 1616, 1513, 1247
cm-¹; ¹H NMR (300 MHz, CDCl3): δ = 7.16 (d, J = 9.0 Hz, 2 H), 6.73 (d, J = 9.0 Hz, 2 H), 5.80-5.68 (m, 1 H), 5.23-5.14 (m, 2 H), 4.51-4.48 (m, 1 H), 4.48 (d, J = 11.3 Hz, 1 H), 4.19 (d, J = 11.3 Hz, 1 H), 4.01-3.94 (m, 1 H), 3.73 (s, 3 H), 1.67-1.50 (m, 2 H), 1.07 (d, J = 6.8 Hz, 3 H); ¹³C NMR (75 MHz, CDCl3): δ = 159.2, 138.1, 129.4, 128.6, 117.1, 113.8, 77.6, 69.9, 64.6, 55.2, 43.5, 23.3; MS (ESI): m/z = 237 [M + H]+, 259 [M + Na]+; HRMS (ESI): m/z [M + H]+ calcd for C14H20O3Na: 259.1310; found: 259.1318.

15

Analytical and spectral data of 18: [α]D ²7 -30.5 (c 2.7, CHCl3); IR (KBr): 3426, 2929, 2865, 1709, 1610, 1513, 1455, 1250 cm-¹; ¹H NMR (300 MHz, CDCl3): δ = 7.16 (d, J = 8.7 Hz, 2 H), 6.8 (d, J = 8.7 Hz, 2 H), 5.77-5.65 (m, 1 H), 5.25-5.2 (m, 2 H), 4.51 (d, J = 11.4 Hz, 1 H), 4.25 (d, J = 11.4 Hz, 1 H), 3.77 (s, 3 H), 3.77-3.70 (m, 1 H), 2.41 (t, J = 7.3 Hz, 2 H), 1.91-1.78 (m, 2 H); ¹³C NMR (75 MHz, CDCl3): δ = 179.4, 159.0, 138.0, 130.2, 129.3, 117.6, 113.6, 78.7, 69.7, 55.1, 30.0, 29.9; MS (ESI): m/z = 273 [M + Na]+; HRMS (ESI): m/z [M + H]+ calcd for C14H18O4Na: 273.1102; found: 273.1101.

16

Analytical and spectral data of 15: [α]D ²7 -55.3 (c 1.9, CHCl3); IR (KBr): 2923, 2853, 1729,1613, 1513, 1377, 1248 cm-¹; ¹H NMR (300 MHz, CDCl3): δ = 7.28-7.24 (m, 4 H), 6.91-6.85 (m, 4 H), 5.80-5.68 (m, 2 H), 5.29-5.13 (m, 5 H), 4.54 (d, J = 11.5 Hz, 1 H), 4.51 (d, J = 11.3 Hz, 1 H), 4.27 (d, J = 11.3 Hz, 1 H), 4.21 (d, J = 11.5 Hz, 1 H), 3.82 (s, 3 H), 3.80 (s, 3 H), 3.80-3.72 (m, 2 H), 2.41-2.18 (m, 2 H), 1.96-1.67 (m, 4 H), 1.21 (d, J = 6.2 Hz, 3 H); ¹³C NMR (75 MHz, CDCl3): δ = 172.8, 159.0, 138.5, 138.3, 130.5, 130.3, 129.6, 129.3, 117.5, 117.0, 113.7, 79.1, 76.3, 69.9, 69.8, 67.6, 55.2, 42.2, 30.5, 30.4, 20.5; MS (ESI): m/z = 491 [M + Na]+; HRMS (ESI): m/z [M + H]+ calcd for C28H36O6Na: 491.2409; found: 491.2413.

17

Analytical and spectral data of 3: [α]D ²7 +46.2 (c 1.0, CHCl3); IR (KBr): 3443, 2923, 2855, 1717, 1647, 1448, 1368, 1243 cm-¹; ¹H NMR (300 MHz, CDCl3): δ = 5.58 (dd, J = 15.6, 9.2 Hz, 1 H), 5.41 (dd, J = 15.6, 9.0 Hz, 1 H), 5.14 (dq, J = 11.1, 6.4 Hz, 1 H), 4.15-4.05 (m, 2 H), 2.32-2.25 (m, 1 H), 2.04 (m, 3 H), 1.92-1.71 (m, 2 H), 1.22 (d, J = 6.4 Hz, 3 H); ¹³C NMR (75 MHz, CDCl3): δ = 174.6, 135.8, 132.8, 74.3, 71.8, 67.8, 43.2, 34.3, 31.5, 21.3; MS (ESI): m/z = 223 [M + Na]+.

18

Analytical and spectral data of 33: [α]D ²7 +14.7 (c 1.4, EtOH); IR (KBr): 2931, 2859, 1731, 1645, 1461, 1370, 1248 cm-¹; ¹H NMR (300 MHz, CDCl3): δ = 5.45 (dd, J = 15.8, 9.0 Hz, 1 H), 5.30 (dd, J = 15.8, 8.6 Hz, 1 H), 5.14-5.03 (m, 1 H), 4.08-3.97 (m, 2 H), 2.26-2.20 (m, 1 H), 2.05-1.96 (m, 2 H), 1.95-1.84 (m, 1 H), 1.78-1.71 (m, 2 H), 1.18 (d, J = 6.6 Hz, 3 H), 0.86 (s, 9 H), 0.85 (s, 9 H), 0.04 (s, 6 H), 0.02 (s, 6 H); ¹³C NMR (75 MHz, CDCl3): δ = 174.4, 135.1, 132.4, 75.3, 73.0, 67.5, 44.8, 35.5, 31.5, 25.7, 21.4, 18.1,
-4.3, -4.4, -4.7; MS (ESI): m/z = 429 [M + H]+; HRMS (ESI): m/z [M + H]+ calcd for C22H44O4NaSi2: 451.2675; found: 451.2675.