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Synlett 2012(4): 581-584  
DOI: 10.1055/s-0031-1290338
LETTER
© Georg Thieme Verlag Stuttgart ˙ New York

Concise Syntheses of (7Z,11Z,13E)-Hexadecatrienal and (8E,18Z)-Tetradecadienal

Zengxiao Maa, Xiaomei Yangb, Yushun Zhanga, Xiangzhong Huangc, Yunhai Tao*a,d
a Key Laboratory of Medicinal Chemistry for Natural Resource (Yunnan University), Ministry of Education, School of Chemical Science and Technology, Yunnan University, Kunming 650091, P. R. of China
Fax: +86(871)5035538; e-Mail: cloudsea2000@sina.com;
b Yunnan University of Traditional Chinese Medicine, Kunming 650200, P. R. of China
c Yunnan University of Nationalities, Kunming 650031, P. R. of China
d State Key Laboratory of Elementoorganic Chemistry, Nankai University, Tianjin 300071, P. R. of China
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Publikationsverlauf

Received 19 October 2011
Publikationsdatum:
08. Februar 2012 (online)

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Abstract

Concise and efficient syntheses of (7Z,11Z,13E)-hexadecatrienal, a sex-pheromone component of the citrus leaf miner, and (8E,10Z)-tetradecadienal, the sex pheromone of the horse-chestnut leaf miner were described, starting from the commercially available acetylene and acrolein. The stereoselective formation of E,Z-conjugated double bond relied on cross-coupling between Grignard reagent and (E,Z)-bromodiene. The present syntheses achieved high overall yield (26% of the former and 23% for the latter) and high isomeric purity (97% for the former and 99% for the latter).

Key words

(7Z,11Z,13E)-hexadecatrienal - (8E,10Z)-tetradeca­dienal - 7-bromo-(4Z,6E)-heptadienal - Kumada cross-coupling - hydroboration-oxidation

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Biobest Technical sheet. Pheromone of horse-chestnut leaf miner (www.biobest.be).

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Preparation for Tetraene 8 Potassium bis(trimethylsilyl) amide (75 mL, 75 mmol, 1 M solution in THF) was added dropwise over 30 min to a suspension of freshly prepared phosphonium salt 7 (33 g, 75 mmol) in dry THF (75 mL) at 0 ˚C, under nitrogen. The resulting orange solution was stirred for 1 h at 0 ˚C and then cooled to -78 ˚C. A solution of aldehyde 3 (9.5 g, 50 mmol) in dry THF (100 mL) was added dropwise over 1 h, maintaining the temperature below -70 ˚C. The resulting yellow solution was allowed to warm slowly to r.t. over a period of 3 h and left overnight. Then the reaction mixture was quenched with a sat. solution of NH4Cl (150 mL). After THF was removed by evaporation, the reaction mixture was extracted with PE (3 × 40 mL). The extract was washed with H2O and brine, dried over Na2SO4, and concentrated. The residue was purified through a silica gel column (eluent: PE) to afford tetraene 8 as a colorless oil (11.48 g, 85%, isomeric purity >98%, chemical purity 96%). ¹H NMR (500 MHz, CDCl3): δ = 6.97 (ddd, J = 13.3, 11.6, 1.2 Hz, 1 H, CH=CH), 6.32 (dd, J = 13.3, 1.3 Hz, 1 H, CH=CH), 5.93 (ddd, J = 11.6, 11.1, 1.3 Hz, 1 H, CH=CH), 5.80 (ddt, J = 17.1, 10.1 Hz, 1 H, CH=CH2), 5.43-5.23 (m, 3 H, CH=CH,), 4.98 (d, J = 17.1 Hz, 1 H, Z-CH=CH2), 4.92 (d, J = 10.1 Hz, 1 H, E-CH=CH2), 2.15-1.95 (m, 8 H, CH2), 1.42-1.32 (m, 4 H, CH2CH2). ¹³C NMR (125 MHz, CDCl3): δ = 139.3, 133.2, 131.4, 128.9, 128.3, 126.5, 114.6, 109.3, 33.4, 29.5, 28.9, 28.4, 27.5, 26.8. ESI-HRMS: m/z calcd for C14H21Br [M]+: 268.0827; found: 268.0812.

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Preparation for Tetraene 9 A solution of tetraene 8 (10.72 g, 40 mmol) and NiCl2 (dppp) (54.2 mg, 0.1 mmol) in dry THF (40 mL) was stirred at r.t. for 30 min under an argon atmosphere. EtMgBr (60 mmol) in dry THF (60 mL) was added to the mixture cooled in an ice bath over 30 min. The nickel complex reacts immediately with the Grignard reagent, and the resulting clear-tan reaction mixture is allowed to warm up to r.t. with stirring for 12 h. After the reaction was completed, the mixture was poured into H2O. After THF was removed by evaporation, the reaction mixture was extracted with PE (3 × 30 mL). The extract was washed with H2O and brine, dried over Na2SO4, and concentrated. The residue was purified through a silica gel column (eluent: PE) to afford tetraene 9 as a colorless oil (8.11 g, 93%, isomeric purity >97%, chemical purity 96%). ¹H NMR (500 MHz, CDCl3): δ = 6.30 (ddd, J = 15.0, 11.0, 1.0 Hz, 1 H, CH=CH), 5.99 (ddd, J = 11.0, 10.7, 1.1 Hz, 1 H, CH=CH), 5.80 (ddt, J = 17.1, 10.1 Hz, 1 H, CH=CH2), 5.71 (dtd, J = 15.0, 7.5, 1.1 Hz, 1 H, CH=CH), 5.46-5.26 (m, 3 H, CH=CH), 4.99 (d, J = 17.1 Hz, 1 H, Z-CH=CH2), 4.93 (d, J = 10.1 Hz, 1 H, E-CH=CH2), 2.15-1.95 (m, 10 H, CH2), 1.42-1.32 (m, 4 H, CH2CH2), 1.02 (t, 3 H, J = 7.5 Hz, CH3). ¹³C NMR (125 MHz, CDCl3): δ = 139.4, 136.8, 130.3, 129.7, 129.5, 129.4, 125.1, 114.6, 33.1, 29.6, 29.0, 28.3, 27.8, 27.5, 26.3, 14.0. ESI-HRMS: m/z calcd for C16H26 [M]+: 218.2035; found: 218.2023.

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Spectral Data for Diene 11
¹H NMR (500 MHz, CDCl3): δ = 6.97 (ddd, J = 13.3, 11.6, 1.2 Hz, 1 H, CH=CH), 6.26 (dd, J = 13.3, 1.3 Hz, 1 H, CH=CH), 5.89 (ddd, J = 11.6, 11.1, 1.3 Hz, 1 H, CH=CH), 5.47 (dtd, J = 11.1, 7.5, 1.2 Hz, 1 H, CH=CH), 2.10 (m, 2 H, CH2), 1.42 (m, 2 H, CH2), 0.90 (t, J = 7.5 Hz, 3 H, CH3). ¹³C NMR (125 MHz, CDCl3): δ = 133.5, 133.3, 125.9, 108.6, 29.9, 22.6, 13.7. ESI-HRMS: m/z calcd for C7H11Br [M]+: 174.0044; found: 174.0062.

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Spectral Data for Triene 12
¹H NMR (500 MHz, CDCl3): δ = 6.30 (ddd, J = 15.0, 11.0, 1.0 Hz, 1 H, CH=CH), 5.99 (ddd, J = 11.0, 10.7, 1.1 Hz, 1 H, CH=CH), 5.80 (ddt, J = 17.1, 10.1 Hz, 1 H, CH=CH2), 5.65 (dtd, J = 15.0, 7.5, 1.1 Hz, 1 H, CH=CH), 5.30 (dtd, J = 10.7, 7.5, 1.0 Hz, 1 H, CH=CH), 4.99 (d, J = 17.1 Hz, 1 H, Z-CH=CH2), 4.93 (d, J = 10.1 Hz, 1 H, E-CH=CH2), 2.15-2.00 (m, 6 H, CH2), 1.42-1.32 (m, 8 H, CH2CH2), 0.9 (t, 3 H, J = 7.5 Hz, CH3). ¹³C NMR (125 MHz, CDCl3): δ = 139.5, 134.9, 130.8, 130.3, 126.1, 114.6, 34.1, 32.9, 32.3, 30.1, 29.7, 29.1, 23.1, 14.1. ESI-HRMS: m/z calcd for C14H24 [M]+: 192.1878; found: 192.1861.