Abstract
Stereoselective synthesis of farnesol, (2E, 6E)-3,7,11-trimethyldodeca-2,6,10-tiren-1-ol(1), was carried out using 5-bromo-2-methylpent-2-ene(2) as a starting material. After conversion of 5-bromo-2-methylpent-2-ene(2) to the corresponding iodide compound, 5-(4-methylpent-3-enyl)-2,3-dihydrofuran(4) was obtained by alkylation of 5-lithio-2,3-dihydrofuran with 5-iodo-2-methylpent-2-ene. Ni(0)-catalyzed coupling reaction of the dihydrofuran 4 with MeMgI was proceeded to give (3E)-4,8-dimethylnona-3,7-dien-1-ol(5) in 72% yield. The resultant homoallylic alcohol 5 was converted to the (5E)-6,10-dimethylundeca-5,9-dien-2-one(8) in 4 steps. Compound 8 was condensed with dimethylmethoxycarbonylmethylphosponate in benzene follwed by $NaBH_4$ reduction in EtOH to yield (2E, 6E)-3,7,11-trimethyldodeca-2,6,10-trien-1-ol(1). Ni(0)-catalyzed coupling reaction of MeMgI with dihydrofuran 4 was a key step in this synthesis of farnesol(1).
5-Bromo-2-methylpent-2-ene(2)을 출발물질로하여 farnesol인 (2E, 6E)-3,7,11-trimethyldodeca-2,6,10-trien-1-ol(1)의 입체 선택적 합성을 수행하였다. 5-Bromo-2-methylpent-2-ene(2)을 요오드화시킨 후, 5-lithio-2,3-dihydrofuran과 반응시켜 5-(4-methylpent-3-enyl)-2,3-dihydrofuran(4)을 얻었다. Dihydrofuran 4를 MeMgI와 Ni(O)-촉매 짝지음 반응시켜 (3E)-4,8-dimethylnona-3,7-dien-1-ol(5)을 72%의 수율로 얻었다. 알릴알코올 5를 4단계로 거쳐 (5E)-6,10-dimethylundeca-5,9-dien-2-one(8)으로 변환시켰다. 화합물 8을 벤젠 용매하에서 dimethylmethoxycarbonylmethylphosponate와 반응시킨 다음, 에탄올 용매하에서 $NaBH_4$로 환원시켜서 (2E, 6E)-3,7,11-trimethyldodeca-2,6,10-tiren-1-ol(1)을 얻었다. Dihydrofuran 4와 MeMgI와의 Ni(O)-촉매 짝지음 반응이 본 연구의 farnsol(1)의 합성에서 중요한 단계이다.
