Novel Intramolecular Reactivity of Oximes: Synthesis of Cyclic and Spiro-Fused Imines
摘要:
Under conventional heat (135-145 degrees C) or microwave irradiation and 1 equiv of acetic anhydride, ortho-substituted aryl-oximes undergo a novel sp(3) C-H activated cyclization to produce the corresponding isoindoles, and aliphatic oximes afford the corresponding dihydropyrroles. The cyclization occurs with various substrates in good yield (46-82%) leading to unique spiro-fused and cyclic imines. An initial mechanistic investigation suggests the reaction occurs via a nitrenium or vinyl nitrene intermediate.
through synergistic Pd/Cu-catalyzed dynamic kinetic asymmetricallenylation with racemic allenylic esters. The protocol is suitable for a wide range of substrates including the challenging allenylic esters with less sterically bulky substituents and provided chiral allenylic products bearing 1,3-nonadjacent stereocenters with high levels of enantio- and diastereoselectivities (up to >20:1 dr and >99% ee)
A dual-metal-catalyzed asymmetric [3+2] annulation of 2-vinyloxiranes with the challenging nucleophilic dipoles (imino esters) was achieved. It was successfully applied to the stereodivergent synthesis of structurally rigid spirocyclic framework. A series of spirocompounds bearing a pyrroline and an olefin were synthesized in an enantio- and diastereodivergent manner.
The asymmetric allylation of 1-pyrroline-5-carboxylic esters has been accomplished through a synergistic Pd/Cu catalyst system under mild reaction conditions. The mechanisticstudies suggested that (1) nucleophilic attack is the enantiodiscriminating step; (2) the cooperative action of two chiral reactive species, N-metalated azomethine ylides and π-allylpalladium, is most likely responsible for its
Gold-Catalyzed Cycloisomerization of Alkyne-Containing Amino Acids: Controlled Tuning of C-N vs. C-O Reactivity
作者:Noelia S. Medran、Matías Villalba、Ernesto G. Mata、Sebastián A. Testero
DOI:10.1002/ejoc.201600429
日期:2016.8
Medran, Noelia Soledad. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Rosario. Instituto de Quimica Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquimicas y Farmaceuticas. Instituto de Quimica Rosario; Argentina
菲尔:梅德兰,诺埃莉亚·索莱达。Consejo Nacional de Investigaciones Cientificas y Tecnicas。Centro Cientifico Tecnologico Conicet - 罗萨里奥。Instituto de Quimica Rosario。罗萨里奥国立大学。Facultad de Ciencias Bioquimicas y Farmaceuticas。Instituto de Quimica Rosario;阿根廷
Silver/ThioClickFerrophos-Catalyzed 1,3-Dipolar Cycloaddition and Tandem Addition–Elimination Reaction of Morita–Baylis–Hillman Adducts
The asymmetric 1,3-dipolar cycloaddition of glycineiminoesters to Morita–Baylis–Hillman (MBH) adducts or acetylated MBH adducts is described. The reaction was efficiently catalyzed by AgOAc/(R,Sp)-ThioClickFerrophos at room temperature to afford pyrrolidine derivatives bearing a quaternary carbon as a single diastereomer with excellent enantioselectivity. When a cyclic pyrroline ester was used as
描述了甘氨酸亚氨基酯与 Morita-Baylis-Hillman (MBH) 加合物或乙酰化 MBH 加合物的不对称 1,3-偶极环加成。该反应在室温下被 AgOAc/( R , S p )-ThioClickFerrophos 有效催化,得到具有良好对映选择性的单一非对映异构体季碳吡咯烷衍生物。当使用环状吡咯啉酯代替甘氨酸亚氨基酯作为亲核试剂时,与乙酰化 MBH 加合物的对映选择性串联加成-消除反应以优异的产率和对映选择性进行,从而形成外-烯烃。这些反应的广泛底物范围和产物的可转化性使得能够以光学纯方式快速获得不同的多功能化吡咯烷。