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。
Activation and discovery of earth-abundant metal catalysts using sodium tert-butoxide
作者:Jamie H. Docherty、Jingying Peng、Andrew P. Dominey、Stephen P. Thomas
DOI:10.1038/nchem.2697
日期:2017.6
NaOtBu — an alkoxide salt — enables simple access to low-oxidation-state catalysis using sustainable first-row transition metals (Fe, Co, Mn, Ni). The approach works across a widerange of reductive alkene and alkyne functionlization reactions including hydroboration, hydrosilylation, hydrogenation, hydrovinylation and [2π+2π] cyclization reactions.
Stereoselective Dehydroxyboration of Allylic Alcohols to Access (<i>E</i>)-Allylboronates by a Combination of C–OH Cleavage and Boron Transfer under Iron Catalysis
Iron-catalyzed direct SN2′ dehydroxyboration of allylic alcohols has been developed to access (E)-stereoselective allylboronates. Allylic alcohols with diverse structures and functional groups, especially derived from natural products, underwent smooth transformation. The six-membered ring transition state formed by allylic alcohols and iron–boron intermediate was indicated to be the key component
铁催化的烯丙醇直接 S N 2' 脱羟基硼酸已被开发用于获得 ( E )-立体选择性烯丙基硼酸酯。具有多种结构和官能团的烯丙醇,特别是来自天然产物的烯丙醇,经历了平稳的转变。由烯丙醇和铁-硼中间体形成的六元环过渡态被证明是参与硼基团转移、C-OH键活化和立体选择性控制的关键成分。
Regioselective Cross-Coupling of Allylboronic Acid Pinacol Ester Derivatives with Aryl Halides via <i>Pd-PEPPSI-IPent</i>
作者:Jennifer L. Farmer、Howard N. Hunter、Michael G. Organ
DOI:10.1021/ja308613b
日期:2012.10.24
The cross-coupling reactions of allylboronic acid pinacol ester derivatives with aryl and heteroaryl halides occurred with high selectivity (>97%) at the α-carbon of the allylboron reagent in the presence of Pd-PEPPSI-IPent precatalyst and 5 M KOH in refluxing THF. In the case of trisubstituted allylboronates with different substituents on the olefin, minor olefin geometry isomerization was observed
Total Synthesis of Isohericerin, Isohericenone, and Erinacerin A: Development of a Copper-Catalyzed Methylboronation of Terminal Alkynes
作者:Bohyun Mun、Sangyong Kim、Hongju Yoon、Ki Hyun Kim、Yunmi Lee
DOI:10.1021/acs.joc.7b00920
日期:2017.6.16
Efficient and concise approaches for the synthesis of three bioactive natural products, isohericerin, isohericenone, and erinacerin A, are described in this paper. The key reactions employed include a Mannich reaction with commercially available hydroxybenzoate and subsequent one-pot lactamization to afford the common precursor isoindolinone in 3 steps and a Suzuki–Miyaura coupling reaction to connect