Copper-Mediated Aerobic Synthesis of 3-Azabicyclo[3.1.0]hex-2-enes and 4-Carbonylpyrroles from N-Allyl/Propargyl Enamine Carboxylates
摘要:
Synthetic methods for 3-azabicyclo[3.1.0] hex-2-enes and 4-carbonylpyrroles have been developed that use copper-mediated/catalyzed reactions of N-allyl/propargyl enamine carboxylates under an O-2 atmosphere and involve intramolecular cyclopropanation and carbooxygenation, respectively. These methodologies take advantage of orthogonal modes of chemical reactivity of readily available N-allyl/propargyl enamine carboxylates; the complementary pathways can be accessed by slight modification of the reaction conditions.
Tri- and tetrasubstituted N–H pyrroles were prepared by the simple treatment of vinyl azides with 1,3-dicarbonylcompounds in toluene at 100 °C via 2H-azirine intermediates generated in situ. When the reactions of vinyl azides and 1,3-dicarbonylcompounds were performed in DMF in the presence of a catalytic amount of K2CO3, 1-vinyl-1,2,3-triazoles were obtained via 1,3-dipolar cycloaddition. These
三-和四取代Ñ经由2在100℃下在甲苯中的简单处理乙烯基叠氮化物与1,3-二羰基化合物制备-H吡咯ħ原位产生-azirine中间体。当在催化量的K 2 CO 3存在下,叠氮化乙烯和1,3-二羰基化合物的反应在DMF中进行时,通过1,3-偶极环加成反应获得1-乙烯基-1,2,3-三唑。这些方法利用了叠氮化乙烯基化学反应的正交模式,这可以通过稍微改变反应条件来实现。
Copper-Mediated Oxidative Transformation of N-Allyl Enamine Carboxylates toward Synthesis of Azaheterocycles
synthesis of 3-azabicyclo[3.1.0]hex-2-enes has been developed by intramolecular cyclopropanation of readily available N-allyl enamine carboxylates. Two complementary reaction conditions, CuBr-mediated aerobic and CuBr2-catalyzed-PhIO2-mediated systems effectively induced stepwise cyclopropanation via carbocupration of alkenes. Oxidative cyclopropane ring-opening of 5-substituted 3-azabicyclo[3.1.0]hex-2-enes
pyrrole formation by the reaction of vinylazides with 1,3-dicarbonyl compounds via the 1,2-addition of 1,3-dicarbonyl compounds to 2H-azirine intermediates generated in situ from vinylazides; (ii) the Cu(II)-catalyzed synthesis of pyrroles from alpha-ethoxycarbonyl vinylazides and ethyl acetoacetate through the 1,4-addition reaction of the acetoacetate to the vinylazides. By applying these two methods
Electrochemical Organoselenium Catalysis for the Selective Activation of Alkynes: Easy Access to Carbonyl-pyrroles/oxazoles from <i>N</i>-Propargyl Enamines/Amides
作者:Mrinmay Baidya、Jhilik Dutta、Suman De Sarkar
DOI:10.1021/acs.orglett.3c01355
日期:2023.5.26
Intramolecular electro-oxidative addition of enamines or amides to nonactivated alkynes was attained to access carbonyl-pyrroles or -oxazoles from N-propargyl derivatives. Organoselenium was employed as the electrocatalyst, which played a crucial role as a π-Lewis acid and selectively activated the alkyne for the successful nucleophilic addition. The synthetic strategy permits a wide range of substrate