提出了一种由N-芳基哌啶或N-芳基氮杂环庚烷的级联反应合成吡咯烷-2-甲醛或四氢吡啶-2-甲醛的新方法。从机理上讲,标题化合物的形成涉及通过Cu(OAc)2 / KI / O 2促进的氧化裂解和C–N键的重整,使灭活的环状胺发生前所未有的氧化环收缩。有趣的是,当用PhI(OAc)2代替KI时,可以高效地直接获得相应醛的1,1-二乙酸酯。据我们所知,这是区域选择性C(sp 3)–H键功能化和C(sp 3)–使用铜盐和氧使饱和环胺的N键活化。
Reductive Amination/Cyclization of Keto Acids Using a Hydrosilane for Selective Production of Lactams versus Cyclic Amines by Switching of the Indium Catalyst
作者:Yohei Ogiwara、Takuya Uchiyama、Norio Sakai
DOI:10.1002/anie.201509465
日期:2016.1.26
amines by reductive amination, using an indium/silane combination. This relatively benign and safe catalyst/reductant system tolerates the use of a variety of functional groups, especially ones that are reduction‐sensitive. A direct switch from synthesizing lactams to synthesizing cyclic amines is achieved by changing the catalyst from In(OAc)3 to InI3. This conversion occurs by further reduction of the
Starting from nitroarenes, under hydrosilylation conditions, using a well-defined N-heterocycliccarbeneiron(0) catalyst, (IMes)Fe(CO)4, the corresponding aniline derivatives were produced in 61–92% isolated yields. More impressively, a selective synthesis of cyclic amines such as pyrrolidines, piperidines and azepanes were conducted from levulinic acid, 1,5- and 1,6-keto acids, respectively. The
Synthesis of β-Methylsulfonylated N-Heterocycles from Saturated Cyclic Amines with the Insertion of Sulfur Dioxide
作者:Yan He、Jintao Yang、Qimeng Liu、Xinying Zhang、Xuesen Fan
DOI:10.1021/acs.joc.0c02368
日期:2020.12.4
An efficient synthesis of β-methylsulfonylated N-heterocycles via FeCl3-catalyzed C(sp3)–H dehydrogenation and C(sp2)–H methylsulfonylation of inactivated cyclic amines with the promotion and participation of inorganic sodium metabisulfite and dicumyl peroxide (DCP) has been developed. Notably, bifunctional DCP acted not only as an oxidant to promote the dehydrogenation but also as a methyl radical
Palladium-Catalyzed Formal Cross-Coupling of Diaryl Ethers with Amines: Slicing the 4-<i>O</i>
-5 Linkage in Lignin Models
作者:Huiying Zeng、Dawei Cao、Zihang Qiu、Chao-Jun Li
DOI:10.1002/anie.201712211
日期:2018.3.26
ether bonds (α‐O‐4, β‐O‐4, and 4‐O‐5 linkages) and other C−C bonds. Among the ether bonds, the bond dissociation energy of the 4‐O‐5 linkage is the highest and the most challenging to cleave. To date, 4‐O‐5 ether linkage model compounds have been cleaved to obtain phenol, cyclohexane, cyclohexanone, and cyclohexanol. The first example of direct formal cross‐coupling of diaryl ether 4‐O‐5 linkage models