Efficient Syntheses of the Polyene Fragments Present in Amphidinols

Abstract

The C53-C67 and C53-C65 polyene fragments of ­amphidinols have been synthesized in an efficient and convergent fashion from sorbic acid in good overall yields (30-31%) by ­employing a chemoselective cross-metathesis of a Weinreb amide and a Julia-Kocienski olefination as the key steps.

Key words

cross-metathesis - Julia-Kocienski olefination - amphidinols - polyenes

References and Notes

• 1 Satake M. Murata M. Yasumoto M. Fujita T. Naoki H. J. Am. Chem. Soc.  1991,  113:  9859 
• 2a Paul GK. Matsumori N. Murata M. Tachibana K. Tetrahedron Lett.  1995,  36:  6279 
• 2b Houdai T. Matsuoka S. Murata M. Satake M. Ota S. Oshima Y. Rhodes LL. Tetrahedron  2001,  57:  5551 
• 2c Murata M. Matsuoka S. Matsumori N. Paul GK. Tachibana K. J. Am. Chem. Soc.  1999,  121:  870 
• 2d Paul GK. Matsumori N. Konoki K. Murata M. Tachibana K. J. Mar. Biotech.  1997,  5:  124 
• 2e Paul GK. Matsumori N. Konoki K. Sasaki M. Murata M. Tachibana K. In Harmful and Toxic Algal Blooms. Proceedings of Seventh International Conference on Toxic Phytoplankton   Yasumoto T. Oshima Y. Fukuyo Y. UNESCO; Sendai / Japan: 1996.  p.503-506  
• 2f Echigoya R. Rhodes L. Oshima Y. Satake M. Harmful Algae  2005,  4:  383 
• 2g Morsy N. Houdai T. Matsuoka S. Matsumori N. Adachi S. Oishi T. Murata M. Iwashita T. Fujita T. Bioorg. Med. Chem.  2006,  14:  6548 
• 3 Chang S.-K. Paquette LA. Synlett  2005,  2915 
• 4 Hicks JD. Flamme EM. Roush WR. Org. Lett.  2005,  7:  5509 
• 5 de Vicente J. Huckins JR. Rychnovsky SD. Angew. Chem. Int. Ed.  2006,  45:  7258 
• 6 Ferrié L. Amans D. Reymond S. Bellosta V. Capdevielle P. Cossy J. J. Organomet. Chem.  2006,  691:  5456 
• 7 Ley SV. Cox LR. Meek G. Metten K.-H. Piqué C. Worrall JM. J. Chem. Soc., Perkin Trans. 1  1997,  3299 
• 8 Spino C. Crawford J. Tetrahedron Lett.  1994,  35:  5559 
• 9 Ware RW. Day CS. King SB. J. Org. Chem.  2002,  67:  6174 
• 10 Trost BM. Crawley ML. Chem. Eur. J.  2004,  10:  2237 
• 11 Blakemore PR. Cole WJ. Kocienski PJ. Morley A. Synlett  1998,  26 

12

tert -Butyl-dimethyl-{[(4 E ,6 E ,8 E ,12 E )-pentadeca-4,6,8,12,14-pentaenyl]oxy}-silane (8)
A 9:1 mixture of inseparable E- and Z-isomers; R _f = 0.63 (PE-Et₂O, 9:1). IR (neat): 3012, 2927, 2855, 1651, 1603, 1253, 1100 cm^-1. ¹H NMR (400 MHz, C₆D₆): δ = 6.29 (dtd, J = 17.0, 10.2, 0.7 Hz, 1 H), 6.18-5.97 (m, 5 H), 5.62 (m, 1 H), 5.54 (dt, J = 14.5, 6.7 Hz, 2 H), 5.06 (d, J = 17.0 Hz, 1 H), 4.93 (d, J = 10.1 Hz, 1 H), 3.51 (t, J = 6.2 Hz, 2 H), 2.14 (td, J = 7.4, 7.1 Hz, 2 H), 2.05-1.99 (m, 4 H), 1.56 (tt, J = 7.6, 6.3 Hz, 2 H), 1.00-0.96 (m, 9 H), 0.06-0.03 (m, 6 H). ¹³C NMR (100 MHz, C₆D₆): δ = 137.6 (d), 134.4 (d), 134.0 (d), 133.2 (d), 132.0 (d), 131.7 (d), 131.6 (d), 131.5 (d), 131.4 (d), 115.2 (t), 62.5 (t), 32.5 (t), 32.8 (t), 32.7 (t), 29.5 (t), 26.1 (q), 18.5 (s), -5.2 (q). MS (EI): m/z = 322 (7) [M⁺], 275 (20), 265 (20), 133 (100), 67 (37). ESI-HRMS: m/z calcd for C₂₁H₃₆OSi + Na⁺: 355.2428; found: 355.2429.

13

tert -Butyl-dimethyl-{[(4 E ,6 E ,8 E )-tetradeca-4,6,8,12-tetraenyl]oxy}-silane (10)
R _f = 0.53 (PE-Et₂O, 98:2). IR (neat): 3013, 2928, 2856, 1641, 1101, 993 cm^-1. ¹H NMR (400 MHz, CDCl₃): δ = 6.12-6.01 (m, 4 H), 5.81 (ddt, J = 17.1, 10.3, 6.4 Hz, 1 H), 5.72-5.61 (m, 2 H), 5.02 (ddd, J = 17.1, 3.4, 1.5 Hz, 1 H), 4.97 (m, 1 H), 3.61 (t, J = 6.4 Hz, 2 H), 2.21-2.11 (m, 6 H), 1.64-1.54 (m, 2 H), 0.91-0.87 (m, 9 H), 0.06-0.02 (m, 6 H). ¹³C NMR (100 MHz, CDCl₃): δ = 138.2 (d), 134.0(d), 133.4 (d), 131.4 (d), 131.1 (d), 130.9 (d), 130.8 (d), 114.8 (t), 62.5 (t), 33.5 (t), 32.4 (t), 32.2 (t), 29.1 (t), 26.0 (q), 18.4 (s), -5.3 (q). MS (EI): m/z = 306 (6) [M⁺], 249 (74), 175 (10), 133 (87), 131 (46), 91 (100), 81 (11), 75 (96), 55 (14). ESI-HRMS: m/z calcd for C₁₉H₃₄OSi + Na⁺: 329.2271; found: 329.2271.