The [2+2] cycloaddition of ynamides with the highly polarized reagent Tf2C=CH2 has been developed to regioselectively afford bis(triflyl)aminocyclobutenes in the absence of catalyst under mild conditions. Incidentally, with the ynamides bearing electron‐rich aromatic rings at the C‐terminal, an interesting reactivity switch was observed; a cyclization/hydroxylation sequence yielded 2‐amino‐3‐(trif
酰胺与高极化试剂Tf 2 C = CH 2的[2 + 2]环加成已开发出在温和条件下在不存在催化剂的情况下区域选择性地提供双(三氟乙)氨基环丁烯的方法。顺便说一下,对于在C端带有富电子芳族环的炔基,观察到一个有趣的反应性开关。一个环化/羟基化序列产生2-氨基-3-(triflyl)环丁-2-烯醇。加有醇的氨基环丁烯结构导致通过环化/加氢烷氧基化过程形成氨基环丁烯基醚。此外,通过4个π电子环的制备α-氨基-β,γ-不饱和酮和3-(三氟乙烯)丁a-1,3-二烯-2-胺,证明了官能化的氨基环丁烯作为进一步精细加工的前体的效用。开环。
Metal-Free Synthesis of Highly Substituted Pyridines by Formal [2+2+2] Cycloaddition under Mild Conditions
The synthesis of pyridines through direct intermolecular cycloaddition of alkynes and nitriles is a contemporary challenge in organic synthesis. A Brønsted acid mediated formal [2+2+2] cycloaddition of heteroalkynes and nitriles was developed that proceeds under mild conditions. This constitutes a modular approach to highly substituted pyridine cores.
With Et3N·3HF as the fluorination reagent, (IPr)CuF-catalyzed α-site regiocontrolled trans-hydrofluorination of ynamides has been achieved, affording (Z)-α-fluoroenamides in moderate to excellent yields. It was interesting to note that the regioselectivity of the reaction is reversed to that observed in the (Ph3P)3CuF-catalyzed hydrofluorination of ynamides. Additionally, a variety of different ynamides
Palladium‐Catalyzed Silylcyanation of Ynamides: Regio‐ and Stereoselective Access to Tetrasubstituted 3‐Silyl‐2‐Aminoacrylonitriles
作者:Pierre Hansjacob、Frédéric R. Leroux、Vincent Gandon、Morgan Donnard
DOI:10.1002/anie.202200204
日期:2022.3.28
Tetrasubstituted 2-aminoacrylonitriles (α-enaminonitriles) are underinvestigated building blocks due to the lack of methodologies to synthesize them in a controlled manner. A general access to these valuable scaffolds accompanied by mechanistic investigations and DFT calculations is described. This highly regio- and stereoselective strategy relies on the use of the first intermolecular silylcyanation
Heterogeneously catalyzed selective aerobic oxidative cross-coupling of terminal alkynes and amides with simple copper(ii) hydroxide
作者:Xiongjie Jin、Kazuya Yamaguchi、Noritaka Mizuno
DOI:10.1039/c2cc31159c
日期:——
Simplecopper(II) hydroxide Cu(OH)(2) could act as an efficient heterogeneous catalyst for selectiveoxidative cross-coupling of a broad range of terminal alkynes and amides using air as a sole oxidant, giving the corresponding ynamides in moderate to high yields (56-93% yields).