端末エポキシドをガンマ-ブタノリドに変換する直接的な方法
Mohammad Movassaghi1, Eric N Jacobsen
1Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, MA 02138, USA.
Journal of the American Chemical Society
|March 14, 2002
まとめ
この研究は,新しいルイス酸触媒反応を使用して,ターミナルエポキシドからガンマ-ブタノリドを合成するための効率的な方法を紹介しています. このプロセスは,複雑な機能群とエナティオメリックに濃縮されたエポキシドからでも,高量のガンマ-ブタノリドを生成します.
科学分野:
- 有機化学 オーガニック・ケミストリー
- 合成化学 合成化学とは
背景:
- ターミナルエポキシドは,有機合成における汎用的な構成要素である.
- ガンマブタノリドは,多くの天然製品や医薬品に含まれる重要な構造モチーフです.
研究 の 目的:
- 末端エポキシドからガンマブタノリドの新しく効率的な合成経路を開発する.
- エポキシードリング開封のためのイナミンを含む,ルイス酸が促進した新しい反応を探求するため.
主な方法:
- 1-モルフォリノ-2-トリメチルシリルアセチレンに末端エポキシドのルイス酸触媒添加.
- 中間サイクルケテネアミナルの水解とプロトデシル化.
- 反応中間物質の特徴を特定するために,光譜モニタリング (IR,NMR) を行います.
主要な成果:
- ガンマ-ブタノリドの高収量は,軽い2段階のプロセスを通して達成されました.
- この反応は,周期性ケテネアミナルの中間体を通して進行する.
- エナティオメリで濃縮された末端エポキシドは,光学活性を失うことなく,相応のガンマ-ブタノリドを生成しました.
- この方法は,さまざまな機能群との互換性を実証しました.
結論:
- 末端エポキシドからガンマ・ブタノリドを合成するための新しい,効率的で汎用的な方法が確立されました.
- この方法論は,既存の合成戦略に価値ある代替案を提供し,ステレオ化学と機能的グループ耐性を保ちます.
関連する概念動画
03:00Preparation of Epoxides
9.0K
Overview
Epoxides result from alkene oxidation, which can be achieved by a) air, b) peroxy acids, c) hypochlorous acids, and d) halohydrin cyclization.
Epoxidation with Peroxy Acids
Epoxidation of alkenes via oxidation with peroxy acids involves the conversion of a carbon–carbon double bond to an epoxide using the oxidizing agent meta-chloroperoxybenzoic acid, commonly known as MCPBA. Since the O–O bond of peroxy acids is very weak, the addition of electrophilic oxygen of peroxy acids to...
Epoxides result from alkene oxidation, which can be achieved by a) air, b) peroxy acids, c) hypochlorous acids, and d) halohydrin cyclization.
Epoxidation with Peroxy Acids
Epoxidation of alkenes via oxidation with peroxy acids involves the conversion of a carbon–carbon double bond to an epoxide using the oxidizing agent meta-chloroperoxybenzoic acid, commonly known as MCPBA. Since the O–O bond of peroxy acids is very weak, the addition of electrophilic oxygen of peroxy acids to...
9.0K
02:26Base-Catalyzed Ring-Opening of Epoxides
9.9K
Due to their highly strained structures, epoxides can readily undergo ring-opening reactions through nucleophilic substitution, either in the presence of an acid or a base. The nucleophilic substitution reactions in the presence of acid are called acid-catalyzed ring-opening reactions, and nucleophilic substitution reactions in the presence of a base are called base-catalyzed ring-opening reactions. Epoxides undergo base-catalyzed ring-opening reactions in the presence of a strong nucleophile...
9.9K
02:57Sharpless Epoxidation
4.9K
The conversion of allylic alcohols into epoxides using the chiral catalyst was discovered by K. Barry Sharpless and is known as Sharpless epoxidation. The use of a chiral catalyst enables the formation of one enantiomer of the product in excess. This chiral catalyst is mainly a chiral complex of titanium tetraisopropoxide and tartrate ester (specific stereoisomer). The stereoisomer used in the chiral catalyst dictates the formation of the enantiomer of the product. In other words, the use of...
4.9K
02:24Acid-Catalyzed Ring-Opening of Epoxides
8.6K
Epoxides that are three-membered ring systems are more reactive than other cyclic and acyclic ethers. The high reactivity of epoxides originates from the strain present in the ring. This ring strain acts as a driving force for epoxides to undergo ring-opening reactions either with halogen acids or weak nucleophiles in the presence of mild acid. The acid catalyst converts the epoxide oxygen, a poor leaving group, into an oxonium ion, a better leaving group, making the reaction feasible. The...
8.6K
03:08Hydroboration-Oxidation of Alkenes
10.9K
In addition to the oxymercuration–demercuration method, which converts the alkenes to alcohols with Markovnikov orientation, a complementary hydroboration-oxidation method yields the anti-Markovnikov product. The hydroboration reaction, discovered in 1959 by H.C. Brown, involves the addition of a B–H bond of borane to an alkene giving an organoborane intermediate. The oxidation of this intermediate with basic hydrogen peroxide forms an alcohol.
10.9K
02:04Oxidation of Alkenes: Anti Dihydroxylation with Peroxy Acids
7.1K
Diols are compounds with two hydroxyl groups. In addition to syn dihydroxylation, diols can also be synthesized through the process of anti dihydroxylation. The process involves treating an alkene with a peroxycarboxylic acid to form an epoxide. Epoxides are highly strained three-membered rings with oxygen and two carbons occupying the corners of an equilateral triangle. This step is followed by ring-opening of the epoxide in the presence of an aqueous acid to give a trans diol.
7.1K