14 マイケル付加を利用する隣接三級炭素の立体制御と天然物合成への応用
スポンサーリンク
概要
- 論文の詳細を見る
Stereocontrolled construction of the adjacent tertiary carbons was examined using the Michael addition of ester and amide enolates to α,β-unsaturated esters. It was applied to the stereoselective synthesis of natural products possessing acyclic or extracyclic chiral centers. Reaction of lithiated propionates with crotonates in THF-HMPA at -78℃ gave erythro-2,3-dimethylglutarates highly selectively. Threo-isomers were synthesized by using t-butyl propionate (1b) in THF. A formal synthesis of faranal (6), the trail pheromone of monomorium pharaonis, was performed. When ω-halo-2-alkenoates (10) were treated with the enolate in the presence of t-BuOK, the Michael-induced intramolecular alkylation occurred smoothly. And cycloalkanes were obtained as a single isomer concerning three chiral centers containing an extracyclic center. (+)-Dehydroiridodiol (12), isolated from Actinidia polygama Miq. as an attractant for members of the Chrysopidae, and (+)-isodehydroiridodiol (13) were synthesized stereoselectively. The enolate of N-propionylpyrrolidine (18a) reacted with the unsaturated esters in ether to give threo-adducts. The other isomer was synthesized by using 2,5-trans-disubstituted pyrrolidine amide 18b. The asymmetric Michael addition was performed with (L)-N-methyl-N-propionylvalinol (18c), and, after the hydrolysis of ester and amide group, (2R,3R)-2,3-dimethylglutaric acid (erythro-22) was obtained. (L)-N-Propionyl-prolinol (18d) afforded (2R,3S)-acid (threo-22). The synthesis of (+)-12 and (-)-13 was achieved utilizing this methodology.
- 天然有機化合物討論会の論文
- 1985-09-07
著者
関連論文
- 90 Urdamycinone Bの全合成(口頭発表の部)
- ポリケチドを用いる有機合成反応--ポリケトエステルの分子内縮合反応およびBF3-促進クライゼン縮合反応に関する研究
- 81 Polyketide型生合成反応をモデルとする多環性芳香族化合物の新合成法
- 14 マイケル付加を利用する隣接三級炭素の立体制御と天然物合成への応用
- Polyketide型化合物を利用する多環性芳香族化合物の新合成法
- マイケル付加反応を利用する隣接三級不斉炭素の立体制御