Synthesis of Highly Substituted Pyridines through Copper-Catalyzed Condensation of Oximes and α,β-Unsaturated Imines
作者:Wei Wen Tan、Yew Jin Ong、Naohiko Yoshikai
DOI:10.1002/anie.201704378
日期:2017.7.3
A copper-catalyzed condensation reaction of oxime acetates and α,β-unsaturated ketimines to give pyridine derivatives is reported. The reaction features mild conditions, high functional-group compatibility, and high regioselectivity with respect to unsymmetrical oxime acetates, thus allowing the preparation of a wide range of polysubstituted pyridines, many of which are not readily accessible by conventional
A hydrazine-free photoredox catalytic synthesis of azines by reductive activation of readily available oxime esters
作者:Jonathan Schütte、Daria Corsi、Wolfgang Haumer、Simon Schmid、Jonas Žurauskas、Joshua P. Barham
DOI:10.1039/d4gc00804a
日期:——
a novel, hydrazine-free photoredox catalyzed platform for azinesynthesis using mild, simple reaction conditions. While previous energy transfer activations of oxime esters lead to decarboxylation of the O-auxiliary and radical combination with the iminyl radical, the reductive electron transfer strategy herein affords high yields of azines using only a triarylamine organophotocatalyst and no additives
Copper‐Catalyzed Aza‐Sonogashira Cross‐Coupling To Form Ynimines: Development and Application to the Synthesis of Heterocycles
作者:Rémi Lavernhe、Rubén O. Torres‐Ochoa、Qian Wang、Jieping Zhu
DOI:10.1002/anie.202110901
日期:2021.11.2
AbstractNitrogen‐substituted alkynes, such as ynamines and ynamides, are versatile synthetic building blocks. Ynimines bearing additional nucleophilic and electrophilic centers relative to ynamines and ynamides are expected to have high synthetic potential. However, their chemical reactivity remains unexplored owing mainly to the lack of synthetic accessibility. We report herein a versatile copper‐catalyzed synthesis of ynimines from readily available O‐acetyl ketoximes and terminal alkynes. A wide range of O‐acetyl ketoximes derived from diaryl ketones, aryl alkyl ketones and dialkyl ketones underwent cross‐coupling with a diverse set of terminal alkynes to afford the ynimines in good to excellent yields. An unprecedented [5+1] heteroannulation reaction exploiting the reactivity of the ynimine generated in situ was subsequently developed for the synthesis of medicinally important heterocycles, including isoquinolines, azaindoles, azabenzofurans, azabenzothiophenes and carbolines.
Synthesis of 2,3-Diaryl-2H-azirines via Cs2CO3-Mediated Cyclization of Ketoxime Acetates