コンプレスタチンAとB (ニューロプロテクチンAとB) の合成とステレオ化学的決定
Steven P Breazzano1, Dale L Boger
1Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, United States.
Journal of the American Chemical Society
|October 14, 2011
まとめ
研究者らは,クロロペプチンII (コンプレスタチン) の新種の酸化によってクロロペプチンAとB (神経保護素) を合成した. この研究は,ステレオ化学的割り当てを確立し,これらの複雑な天然製品への効率的な合成経路を提供します.
科学分野:
- 有機化学 オーガニック・ケミストリー
- 自然製品合成 自然製品の合成
- 薬用化学 薬用化学について
背景:
- クロロペプチンは,潜在的な治療用途を持つ天然製品のクラスです.
- 以前の研究では,クロロペプチンII (コンプレスタチン) の全合成を確立しました.
- クロロロペプチンA (ニューロプロテクチンA) とクロロペプチンB (ニューロプロテクチンB) の立体化学と合成は依然として困難でした.
研究 の 目的:
- クロロロペプチンAとクロロペプチンBのための合成経路を開発する.
- クロロロペプチンAとクロロロペプチンBのステレオ化学的割り当てを確立する.
- クロロロペプチンIIの新しい酸化戦略を探求する.
主な方法:
- クロロペプチンA合成のための2つの異なる単段階インドル酸化方法 (HCl-DMSOとNBS,THF-H2O) を開発した.
- 塩ロペプチンBの合成のために2段階の単一ポット酸化 (NCS,THF-H2O,Cs2CO3,DMF-H2O) を利用しました.
- ステレオ化学を割り当てるために,クロロペプチンIIの合成DEFリングシステムについて広範な研究を行った.
主要な成果:
- クロロロペプチンA (ニューロプロテクチンA) の最初の合成を達成し,優れた収量 (93%と82%).
- ニューロプロテクチンB (クロロペプチンB) を2段階のシングルポット酸化法で合成しました.
- 2つの天然製品のステレオ化学を明確に割り当てました.
結論:
- 開発された酸化方法により,クロロペプチンAおよびBに効率的にアクセスできます.
- この研究は,これらの重要な天然製品のステレオ化学を明らかにします.
- 合成戦略は,クロロペプチンIIの反応性に関する貴重な洞察を提供します.
関連する概念動画
02:05Prochirality
The concept of prochirality leads to the nomenclature of the individual faces of a molecule and plays a crucial role in the enantioselective reaction. It is a concept where two or more achiral molecules react to produce chiral products. A typical process is the reaction of an achiral ketone to generate a chiral alcohol. Here, the achiral reactant reacts with an achiral reducing agent, sodium borohydride, to generate an equimolar mixture of the chiral enantiomers of the product. For example, an...
01:29Diels–Alder Reaction Forming Bridged Bicyclic Products: Stereochemistry
Diels–Alder reactions between cyclic dienes locked in an s-cis configuration and dienophiles yield bridged bicyclic products.
02:33Stereoisomerism of Cyclic Compounds
In this lesson, we delve into the role of ring conformation and its stability, which determines the spatial arrangement and, consequently, the molecular symmetry and stereoisomerism of cyclic compounds. 1,2-Dimethylcyclohexane is used as a case study to evaluate the possible number of stereoisomers. Here, given the multiple (n = 2) chiral centers, there are 2n = 4 possible configurations that lack a plane of symmetry, as the ring skeleton exists in a non-planar chair conformation. In addition,...
02:15SN1 Reaction: Stereochemistry
This lesson provides an in-depth discussion of the stereochemical outcomes in an SN1 reaction.
In the first step of an SN1 reaction, the bond between the electrophilic carbon and the leaving group ionizes to generate the carbocation intermediate. The second step of the mechanism is the nucleophilic attack.
In the formed carbocation, the positively charged carbon is sp2 hybridized with a trigonal planar geometry. As all the three substituents lie on the same plane, a plane of symmetry for the...
In the first step of an SN1 reaction, the bond between the electrophilic carbon and the leaving group ionizes to generate the carbocation intermediate. The second step of the mechanism is the nucleophilic attack.
In the formed carbocation, the positively charged carbon is sp2 hybridized with a trigonal planar geometry. As all the three substituents lie on the same plane, a plane of symmetry for the...
01:13¹H NMR: Complex Splitting
A proton M that is coupled to a proton X results in doublet signals for M. However, NMR-active nuclei can be simultaneously coupled to more than one nonequivalent nucleus. When M is coupled to a second proton A, such as in styrene oxide, each peak in the doublet is split into another doublet.
Splitting diagrams or splitting tree diagrams are routinely used to depict such complex couplings. While drawing splitting diagrams, the splitting with the larger coupling constant is usually applied first.
Splitting diagrams or splitting tree diagrams are routinely used to depict such complex couplings. While drawing splitting diagrams, the splitting with the larger coupling constant is usually applied first.
02:32Stereoisomers
On the basis of mirror symmetry, stereoisomers of an organic molecule can be further classified into diastereomers and enantiomers. Diastereomers are stereoisomers that are not mirror images of each other. Substituted alkenes, such as the cis and trans isomers of 2-butene, are diastereomers, as these molecules exhibit different spatial orientations of their constituent atoms, are not mirror images of each other, and do not interconvert. Here, the interconversion is suppressed due to restricted...