Efficientborylation of sp3 C–O bonds by supported Au catalysts is described. Au nanoparticles supported on TiO2 showed high activity under mild conditions employing low catalyst loading conditions without the aid of any additives, such as phosphine and bases. A variety of allyl, propargyl, and benzyl substrates participated in the heterogeneously catalyzed reactions to furnish the corresponding allyl
描述了负载型Au催化剂对sp 3 C–O键的有效硼化作用。负载在TiO 2上的Au纳米颗粒在温和条件下采用低催化剂负载条件显示出高活性,而无需任何添加剂,例如膦和碱。各种烯丙基,炔丙基和苄基底物参与了非均相催化反应,以高产率提供了相应的烯丙基,烯丙基和苄基硼酸酯。此外,Au / TiO 2对烯丙基和苄基醇的直接硼化也有效。基于Hammett研究和控制实验的机理研究表明,负载型Au催化剂上的sp 3 C–O键硼化通过S N进行1'型机制涉及碳阳离子中间体的形成。负载的金催化剂的高活性,可重复使用性和环境相容性以及反应体系的可扩展性使有价值的有机硼化合物的实际合成成为可能。
Polymeric β-alanine incarcerated Pd(<scp>ii</scp>) catalyzed allylic etherification in water: a mild and efficient method for the formation of C(sp<sup>3</sup>)–O bonds
作者:Mita Halder、Md. Mominul Islam、Sabir Ahammed、Sk. Manirul Islam
DOI:10.1039/c5ra26182a
日期:——
polystyrene and β-alanine. Using this polymer incarcerated palladium(II) catalyst a useful and efficient procedure for stereospecific synthesis of allyl-aryl ethers has been developed. The benzylic, aromatic, and heteroaromatic phenols react with various substituted allyl acetates by this procedure to furnish a library of allyl-aryl and allyl-hetero-aryl ethers in high yields. The catalyst could be recovered
Enantioselective Reductive Homocoupling of Allylic Acetates Enabled by Dual Photoredox/Palladium Catalysis: Access to <i>C</i><sub>2</sub>-Symmetrical 1,5-Dienes
emerged as powerful protocols to construct C–C bonds. However, the development of enantioselective C(sp3)–C(sp3) reductive coupling remains challenging. Herein, we report a highly regio-, diastereo-, and enantioselective reductive homocoupling of allylic acetates through cooperative palladium and photoredox catalysis using diisopropylethylamine or Hantzsch ester as a homogeneous organic reductant.
Solvent-Controlled Highly Selective Bis- and Monoallylation of Active Methylene Compounds by Allyl Acetate with Palladium(0) Nanoparticle
作者:Brindaban C. Ranu、Kalicharan Chattopadhyay、Laksmikanta Adak
DOI:10.1021/ol702099v
日期:2007.10.1
catalyst for the allylation of active methylene compounds. Very efficient bisallylation is achieved for a variety of active methylene compounds by allyl acetate and itsderivatives in one stroke in THF solvent. The reaction in water provides monoallylated product selectively by allyl acetate only. The recovered Pd(0) nanoparticle is recycled. A probable mechanism is suggested.
Synthesis of α,α-disubstituted amino acids based on tandem reaction of dehydroamino acid derivatives
作者:Hideto Miyabe、Ryuta Asada、Yoshiji Takemoto
DOI:10.1016/j.tet.2004.10.104
日期:2005.1
all-substituted sp3-hybridized carbon-center was investigated via tandem reaction of dehydroamino acid derivatives. The diethylzinc-promoted reaction of dehydroamino acid derivatives with acid anhydride or π-allylpalladium complex proceeded smoothly to afford α,α-disubstituted amino acids via a radical and anionic carbon–carbon bond-forming processes. The tandem reductive reaction of N-phthaloyl dehydroalanine