Ni-Catalyzed Formal Cross-Electrophile Coupling of Alcohols with Aryl Halides
作者:Quan Lin、Guobin Ma、Hegui Gong
DOI:10.1021/acscatal.1c04239
日期:2021.11.19
and TBAB as the mild bromination reagents enables rapid transformation of a wide range of alcohols to their bromide counterparts within one to 5 min in CH3CN and DMF, which is compatible with the Ni-catalyzed cross-electrophile coupling conditions in the presence of a chemical reductant. The present method is suitable for arylation of a myriad of structurally complex alcohols with no need for prepreparation
未活化醇的直接偶联仍然是当前合成化学中的一个挑战。我们在此展示了一种建立在醇与芳基卤化物的原位卤化/还原偶联以形成 Csp 2 -Csp 3键的策略。2-氯-3-乙基苯并[ d ]恶唑-3-鎓盐 (CEBO) 和 TBAB 作为温和溴化试剂的组合能够在 CH 3 中在一到 5 分钟内将范围广泛的醇快速转化为其溴化物对应物CN 和 DMF,在化学还原剂存在下与 Ni 催化的交叉亲电偶联条件相容。本方法适用于无数结构复杂的醇的芳基化,而无需制备卤代烷。更重要的是,温和且动力学快速的溴化过程在对称二醇的溴化/芳基化和多元醇中较少的空间位阻羟基中显示出良好的选择性,从而为二醇和多元醇的选择性官能化提供了希望,而无需费力的保护/脱保护操作。这项工作的实用性在许多碳水化合物、药物化合物和天然醇的芳基化中也很明显。
The Synthesis of Oxiranes and Oxetanes from 1,2- or 1,3-Halohydrins Using Organoantimony(V) Alkoxide
Tetraphenylstibonium methoxide (1) is an effective reagent for the synthesis of oxiranes and oxetanes from the corresponding 1,2- and 1,3-halohydrins, respectively. As the reaction conditions are neutral, oxiranes bearing an ester moiety were obtained intact without undergoing solvolysis. In addition, oxetanes, whose preparation was not generally facile, were formed in good yields under mild conditions (60-80°C).
Copper-Catalyzed C–H Fluorination/Functionalization Sequence Enabling Benzylic C–H Cross Coupling with Diverse Nucleophiles
作者:Aristidis Vasilopoulos、Dung L. Golden、Joshua A. Buss、Shannon S. Stahl
DOI:10.1021/acs.orglett.0c02238
日期:2020.8.7
Site-selective transformation of benzylic C–H bonds into diversefunctional groups is achieved via Cu-catalyzed C–H fluorination with N-fluorobenzenesulfonimide (NFSI), followed by substitution of the resulting fluoride with various nucleophiles. The benzyl fluorides generated in these reactions are reactive electrophiles in the presence of hydrogen-bond donors or Lewis acids, allowing them to be used
Synthesis of piperazine derivatives and evaluation of their antihistamine and antibradykinin effects
作者:Hea-Young Park Choo、Bum-Jun Chung、Sung-Hyun Chung
DOI:10.1016/s0960-894x(99)00471-0
日期:1999.9
Piperazine derivatives were prepared as histamineantagonists. Some of the synthesized compounds showed dual antagonistic activity against bradykinin as well as histamine.
Six-Membered, Chiral NHCs Derived from Camphor: Structure–Reactivity Relationship in Asymmetric Oxindole Synthesis
作者:Markus J. Spallek、Dominic Riedel、Frank Rominger、A. Stephen K. Hashmi、Oliver Trapp
DOI:10.1021/om201166b
日期:2012.2.13
A series of three chiral, expanded six-membered NHC–palladium(II) complexes was prepared with successively increased sterical demand, while retaining natural d-(+)-camphor as a chiral motif. The catalysts showed different reaction profiles in the asymmetric, intramolecularα-arylation of amides. The molecular structure of two N-heterocyclic and one nitrogen acyclic carbene palladium isonitrile complex