タンデム触媒性アリルアミネーションと[2,3]-スティーブンスの三次アミンの再配置
Arash Soheili1, Uttam K Tambar
1Department of Biochemistry, Division of Chemistry, The University of Texas Southwestern Medical Center at Dallas, 5323 Harry Hines Boulevard, Dallas, Texas 75390-9038, USA
Journal of the American Chemical Society
|July 29, 2011
まとめ
この研究では,三次アミンを用いた触媒性アリルアミネーションを導入し,新しいパラジウム触媒性スティーブンスの再配置を可能にします. この方法は,温和な条件下で高い収穫量と選択性を達成し,広範囲の基板の適用範囲があります.
科学分野:
- 有機化学 オーガニック・ケミストリー
- カタリシス カタリシス カタリシス
- 合成方法論 合成方法論
背景:
- 三次アミンは,金属触媒によるアリル置換において,典型的には貧弱な核愛素である.
- C-N結合形成のための新しい方法の開発は,有機合成において極めて重要です.
研究 の 目的:
- 三次アミンを核愛素として使用した新しい触媒性アリルアミナーション反応を開発する.
- パラジウム触媒によるスティーブンスの再配列を模倣して,アンモニアムイライド生成と[2,3]再配列を含むタンデム反応を確立する.
主な方法:
- 基板として利用された三次アミノエステルとアリルカルボネート.
- アリル基の置換と再配置のためにパラジウム触媒を用いた.
- 調査された反応条件,触媒の負荷,および基板の範囲.
- 反応経路を明らかにするために,メカニズム研究を実施した.
主要な成果:
- 金属触媒によるアルリル置換における三次アミンによる分子間核性攻撃の最初の例を達成した.
- タンデムアンモニアムイライド生成/[2,3]再配列,パラジウム触媒によるスティーブンス再配列を開発した.
- 穏やかな条件下での幅広い基板との互換性が実証されています.
- 得られた製品は,高い収穫量と優れたダイアステレオ選択性を持っています.
- 機械学的研究は,可逆的なアンモニアの中間生成を示した.
結論:
- 開発された触媒システムは,複雑な分子を合成するための効率的な経路を提供します.
- この研究は,触媒性C−N結合形成反応における三次アミンの有用性を拡大する.
- タンデム反応は,価値ある有機構造にアクセスするための強力な戦略を提供します.
関連する概念動画
01:07Preparation of 1° Amines: Hofmann and Curtius Rearrangement Overview
In the presence of an aqueous base and a halogen, primary amides can lose the carbonyl (as carbon dioxide) and undergo rearrangement to form primary amines. This reaction, called the Hofmann rearrangement, can produce primary amines (aryl and alkyl) in high yields without contamination by secondary and tertiary amines.
01:38Preparation of Amines: Reductive Amination of Aldehydes and Ketones
Carbonyl compounds and primary amines undergo reductive amination first to produce imines, followed by secondary amines in the same reaction mixture, using selective reducing agents like sodium cyanoborohydride or sodium triacetoxyborohydride. Reductive amination produces different degrees of substitution of amines depending on the starting amine substrate.
01:26Preparation of 1° Amines: Hofmann and Curtius Rearrangement Mechanism
The Hofmann and Curtius rearrangement reactions can be applied to synthesize primary amines from carboxylic acid derivatives such as amides and acyl azides. In the Hofmann rearrangement, a primary amide undergoes deprotonation in the presence of a base, followed by halogenation to generate an N-haloamide. A second proton abstraction produces a stabilized anionic species, which rearranges to an isocyanate intermediate via an alkyl group migration from the carbonyl carbon to the neighboring...
01:30Preparation of Amines: Alkylation of Ammonia and Amines
Alkylation is one of the methods used to prepare amines. Direct alkylation of ammonia or a primary amine with an alkyl halide gives polyalkylated amines along with a quaternary ammonium salt through successive SN2 reactions. This process of making the quaternary salt through the direct alkylation method is called exhaustive alkylation.
Each alkylation step makes the nitrogen center more nucleophilic, which triggers successive alkylations until a quaternary ammonium salt is formed. Considering...
Each alkylation step makes the nitrogen center more nucleophilic, which triggers successive alkylations until a quaternary ammonium salt is formed. Considering...
01:28Preparation of 1° Amines: Gabriel Synthesis
Direct alkylation is not a suitable method for synthesizing amines because it produces polyalkylated products. Gabriel synthesis is the most preferred method to exclusively make primary amines. The method uses phthalimide, which contains a protected form of nitrogen that participates in alkylation only once to predominantly give primary amines.
Strong bases like NaOH or KOH deprotonate the phthalimide to form the corresponding anion, which acts as a nucleophile. Further, the anion attacks an...
Strong bases like NaOH or KOH deprotonate the phthalimide to form the corresponding anion, which acts as a nucleophile. Further, the anion attacks an...
01:19Amines to Amides: Acylation of Amines
Various carboxylic acid derivatives (such as acid chlorides, esters, and anhydrides) can be used for the acylation of amines to yield amides. The reaction requires two equivalents of amines. The first amine molecule functions as a nucleophile and attacks the carbonyl carbon to produce a tetrahedral intermediate. This is followed by the loss of the leaving group and restoration of the C=O bond.
Next, the second equivalent of amine serves as a Brønsted base and deprotonates the quaternary amide...
Next, the second equivalent of amine serves as a Brønsted base and deprotonates the quaternary amide...