Selective C−O Bond Cleavage of Sugars with Hydrosilanes Catalyzed by Piers’ Borane Generated In Situ
作者:Jianbo Zhang、Sehoon Park、Sukbok Chang
DOI:10.1002/anie.201708109
日期:2017.10.23
[(C6F5)2BH], generated in situ, is demonstrated to promote the hydrosilylative reduction of sugars, providing a series of linear or cyclic polyols with high chemo- and regioselectivities undermildconditions. Studies of catalytic reactivity and regioselectivity with regard to the C−O bond cleavage with hydrosilanes suggest an importance of the steric environment around the anomeric carboncenter of the
Piers的硼烷[(C 6 F 5)2 BH]原位生成,可促进糖的氢化硅烷化还原,在温和条件下提供一系列具有高化学选择性和区域选择性的线性或环状多元醇。关于用氢硅烷裂解C-O键的催化反应性和区域选择性的研究表明,糖异头碳中心周围的空间环境很重要。
Construction of C–O bond via cross-dehydrogenative coupling of sp [ ] C–H bond with phenols catalyzed by copper porphyrin
Copper porphyrin-catalyzed construction of ether bond by cross-dehydrogenative coupling of sp [3] C–H bond with phenols bearing electron-withdrawing groups (EWG) was described for the first time. A broad range of substrates afforded different acetals in moderate to excellent yields with good functional group tolerance. The developed method is not only suitable for phenol substrates with ortho-directing
Piers’ borane-mediated hydrosilylation of epoxides and cyclic ethers
作者:Jianbo Zhang、Sehoon Park、Sukbok Chang
DOI:10.1039/c8cc03741h
日期:——
diarylborane-catalysed hydrosilylation of epoxides and cyclicethers. Mechanistic studies on the in situ generated Piers’ borane (C6F5)2BH with hydrosilanes in the presence of an epoxide revealed that an alkyloxy(diaryl)borane (C6F5)2BOR is readily formed as a catalytically competent species for the outer-sphere hydrosilylation of epoxides and cyclicethers.
我们报道了环氧化物和环醚的第一个二芳基硼烷催化的氢化硅烷化反应。在环氧化物存在下与氢硅烷原位生成Piers's硼烷(C 6 F 5)2 BH的机理研究表明,烷氧基(二芳基)硼烷(C 6 F 5)2 BOR易于形成为催化活性物质用于环氧化物和环醚的外球氢化硅烷化。
Silver-Catalyzed, <i>N</i>-Formylation of Amines Using Glycol Ethers
作者:Bradley H. King、Michelle L. Wang、Kate A. Jesse、Guneet Kaur、Brianna Tran、Ryan Walser-Kuntz、Robert G. Iafe、Anna G. Wenzel
DOI:10.1021/acs.joc.0c01552
日期:2020.10.16
A silver-catalyzed protocol was found to afford the N-formylation of amines in moderate-to-good yields. Ethylene glycol-derived, oligomeric ethers were found to function as the formylating agent, with 1,4-dioxane affording the best results. This reaction does not require the use of stoichiometric activating reagents, and avoids the use of explosive reagents or toxic gases, such as CO, as the C1 synthon
Cobalt-Catalyzed Cross-Dehydrogenative C(sp<sup>2</sup>
)−C(sp<sup>3</sup>
) Coupling of Oxazole/Thiazole with Ether or Cycloalkane
作者:Xiaojiao Wang、Bowen Lei、Lifang Ma、Lisi Zhu、Xinyue Zhang、Hao Zuo、Dailin Zhuang、Ziyuan Li
DOI:10.1002/asia.201701258
日期:2017.11.2
Direct C5‐alkylation of oxazole/thiazole with ether or cycloalkane has been achieved through a cobalt‐catalyzed cross‐dehydrogenative coupling (CDC) process in moderate to good yields. This transformation represents the first C(sp2)−C(sp3) cross‐coupling at the C5‐position of the oxazole/thiazole via double C−H bond cleavages. Various functional groups on oxazole/thiazole substrates, as well as water