P-30 キラルケトンの絶対配置決定法(ポスター発表の部)
スポンサーリンク
概要
- 論文の詳細を見る
Optically active α-substituted ketones (α-chiral ketones) are versatile intermediates for the synthesis of natural products, especially in terpene or pheromone synthesis. A number of methods for the synthesis of α-chiral ketones have been reported. However, few studies are found in the literature for the direct method to determine the absolute configurations of these chiral ketones. They have been determined by derivation to the known compounds or assumed from empirical rules. X-Ray crystallographic analysis is the only method to determine the absolute configuration of a molecule. The anomalous dispersion effect of a heavy atom must be used for the determination of the absolute configuration. Hydrazines are well-known to be good crystalline agents for ketones. It is easy that a halogen atom as a heavy atom is introduced into a phenyl ring in the phenylhydrazine. Thus, a phenylhydrazine derivative having (a) halogen atom(s) is employed as a crystalline agent. We designed and syntesized some hydrazines as crystalline agents, and found that 2-chloro-4,6dinitrophenylhydrazine is the useful crystalline agent for various chiral ketones. The reaction of the hydrazine and a chiral ketone gave the single crystal suitable for X-ray crystallographic analysis. The crystal structure and absolute configuration of the corresponding hydrazone was determined using the anomalous dispersion effect of a chlorine atom. This is the simple and direct method and the potential of this methodology was clearly demonstrated. It should be noted that 2-chloro-4,6-dinitrophenylhydrazine is a useful crystalline agent for this purpose. This method can be applied to both of aromatic and aliphatic chiral ketones, and is helpful for the determination of the absolute configuration of various chiral ketones.
- 天然有機化合物討論会の論文
- 2005-09-15