由于α-立体中心的敏感性,具有最小外消旋化的手性氨基酸酯的N-芳基化是具有挑战性的转化。开发了一种通用的合成方法,以在连续流动条件下使用环己酮作为芳基来源制备N-芳基化氨基酸酯。设计的流动系统由盘管反应器和含有 Pd(OH) 2 /C 催化剂的填充床反应器组成,有效地提供了所需的N-芳基化氨基酸,而没有显着的外消旋化,仅伴随少量易于去除的共聚反应。 - 产品(即,H 2O 和烷烃)。该方法的效率和稳健性允许以非常高的产率和对映体纯度连续合成所需的产物,同时具有高时空产率(74.1 g L -1 h -1)和周转频率(5.9 h -1)至少持续3天。
compounds remains an unsolved issue. Reported here is a nickel‐catalyzed trans‐selective dicarbofunctionalization of N‐Boc‐2‐pyrroline and N‐Boc‐2‐azetine, a class of endocyclic enecarbamates previously unexplored for transition metal catalyzed dicarbofunctionalization. The reaction can be extended to six‐ and seven‐membered endocyclic enamides. A variety of arylzinc reagents and bromodifluoroacetate
Amino Acid Esters and Amides for Reductive Amination of Mucochloric Acid: Synthesis of Novel γ-Lactams, Short Peptides and Antiseizure Agent Levetiracetam (Keppra®)
作者:Koushik Das Sarma、Ji Zhang、Yun Huang、James G. Davidson
A novel aggregation-induced emission enhancement triggered by the assembly of a chiral gelator: from non-emissive nanofibers to emissive micro-loops
作者:Wenrui Chen、Guangyan Qing、Taolei Sun
DOI:10.1039/c6cc08808b
日期:——
In this study, a novel aggregation-induced emission (AIE) enhancement triggered by the self-assembly of chiral gelator is described. Tuning of molecular chirality in situ triggers different assemblies of superstructures exhibiting...
Chemoselective amide reductions by heteroleptic fluoroaryl boron Lewis acids
作者:Michael T. Peruzzi、Qiong Qiong Mei、Stephen J. Lee、Michel R. Gagné
DOI:10.1039/c8cc01863d
日期:——
The heteroleptic borane catalyst (C6F5)2B(CH2CH2CH2)BPin is found to hydrosilylatively reduce amides under mild conditions. Simple tertiary amides can be reduced using Me2EtSiH, whereas tertiary benzamides required a more reactive secondary silane, Et2SiH2, for efficient reduction. The catalytic system described exhibits exceptional chemoselectivity in the reduction of oligoamides and tolerates functionalities
Accessing Aliphatic Amines in C–C Cross-Couplings by Visible Light/Nickel Dual Catalysis
作者:Weizhe Dong、Shorouk O. Badir、Xuange Zhang、Gary A. Molander
DOI:10.1021/acs.orglett.1c01207
日期:2021.6.4
desilylation of α-silylamines upon single-electron transfer (SET) facilitated by carbonate, α-amino radicals are generated regioselectively, which then engage in nickel-mediated C–C coupling. The reaction displays high chemoselectivity for C–C over C–N bond formation. Highly functionalized pharmacophores and peptides are also amenable.