電子欠乏ヘテロサイクルをアリルボロン酸で直接C−Hアリレーションする
Ian B Seiple1, Shun Su, Rodrigo A Rodriguez
1Department of Chemistry and Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, USA.
Journal of the American Chemical Society
|September 4, 2010
まとめ
新しい直接アリレーション法により,室温で安価な銀酸塩とパルスルファートを使用して,多様なアリレーションヘテロサイクルを効率的に合成することができます. このアプローチは,幅広い範囲を提供し,敏感な機能群を許容し,複雑な分子へのアクセスを簡素化します.
科学分野:
- 有機化学 オーガニック・ケミストリー
- 合成方法論 合成方法論
- ヘテロサイクル化学 ヘテロサイクル化学
背景:
- 直接アリレーションは,伝統的なクロスカップリング反応と比較して,ビアリル化合物へのより原子経済的な経路を提供します.
- 電子欠乏ヘテロサイクルは,医薬品化学と材料科学における重要な支架ですが,それらの直接的アリレーションは困難です.
研究 の 目的:
- 電子欠乏ヘテロサイクルの直接アリレーションのための新しい,効率的で費用対効果の高い方法を開発する.
- ヘテロサイクルを含む直接のアリレーション反応に対する基板の範囲と機能群の耐性を拡大する.
主な方法:
- この研究では,パルスルファート (persulfate) の共酸化物質の存在下での触媒として,触媒性銀酸ナイトレットを用いた.
- この反応は室温で行われ,様々な電子欠乏ヘテロサイクルとアリルボロン酸を結合パートナーとして使用した.
主要な成果:
- 幅広い電子欠乏ヘテロサイクルは,アリルボロン酸でアリレーションが成功しました.
- この反応は高機能群耐性を示し,両カップリングパートナーの敏感な部分に対応した.
- この方法は,温和な条件下で多様なアリラートヘテロサイクルの迅速なアクセスを提供しました.
結論:
- 電子欠乏ヘテロサイクルのための新しい実用的な直接アリレーションプロトコルが確立されました.
- この方法は,伝統的な合成戦略に価値ある代替案を提供し,複雑なアリラートヘテロサイクルの化合物への効率的なアクセスを可能にします.
- 安価な反応剤と温和な条件の使用は,この方法論をより広範な合成アプリケーションに魅力的にします.
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Introduction
One of the convenient methods for the preparation of aldehydes and ketones is via hydration of alkynes. Hydroboration-oxidation of alkynes is an indirect hydration reaction in which an alkyne is treated with borane followed by oxidation with alkaline peroxide to form an enol that rapidly converts into an aldehyde or a ketone. Terminal alkynes form aldehydes, whereas internal alkynes give ketones as the final product.
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Introduction
Halogenation is another class of electrophilic addition reactions where a halogen molecule gets added across a π bond. In alkynes, the presence of two π bonds allows for the addition of two equivalents of halogens (bromine or chlorine). The addition of the first halogen molecule forms a trans-dihaloalkene as the major product and the cis isomer as the minor product. Subsequent addition of the second equivalent yields the tetrahalide.
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In the Sandmeyer reaction, for example, the diazonio group is replaced by a chloro, bromo, or cyano...
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