N-Heterocyclic Carbene-Catalyzed Enantioselective Synthesis of Spiro-glutarimides via α,β-Unsaturated Acylazoliums
作者:Santigopal Mondal、Arghya Ghosh、Subrata Mukherjee、Akkattu T. Biju
DOI:10.1021/acs.orglett.8b01799
日期:2018.8.3
NHC-catalyzed enantioselective [3 + 3] spiro-annulation of α,β-unsaturated aldehydes with cyclic β-ketoamides allowing the preparation of synthetically and biologically important spiro-glutarimide derivatives has been reported. The interception of the ketoamides with catalytically generated chiral α,β-unsaturatedacylazoliums proceeds in a Michael addition–intramolecular amidation pathway to deliver
PPh<sub>3</sub>-Catalyzed [3 + 2] Spiroannulation of 1<i>C</i>,3<i>N</i>-Bisnucleophiles Derived from Secondary β-Ketoamides with δ-Acetoxy Allenoate: A Route to Functionalized Spiro <i>N</i>-Heterocyclic Derivatives
作者:Jiaojiao Xing、Yu Lei、Yu-Ning Gao、Min Shi
DOI:10.1021/acs.orglett.7b00910
日期:2017.5.5
A [3 + 2] annulation of α-substituted secondary β-ketoamides with δ-acetoxy-modified allenoate has been developed in the presence of phosphine catalyst. In this spiroannulation reaction, β-ketoamides were used as the bis-nucleophilic partner while the γ,δ-carbon of 5-acetoxypenta-2,3-dienoate participated as a C2 synthon, affording the desired functionalized five-membered N-heterocyclic derivatives
The first organocatalytic general, efficient and highly enantioselective α‐hydroxyamination reactions of β‐ketoamides with nitrosobenzene are described using a thiourea/tertiary amine bifunctional catalyst. Significantly, the products were obtained in high enantiomeric purity using a low catalyst loading, and in the context of sustainable development, the full reaction mixture, including solvent, catalyst
Continuous Flow Generation of Acylketene Intermediates via Nitrogen Extrusion
作者:Harry R. Smallman、Guilherme A. Brancaglion、Julio C. Pastre、Duncan L. Browne
DOI:10.1021/acs.joc.2c01486
日期:2022.9.16
of acylketene precursors through extrusion of nitrogen gas is reported. Key to the development of a suitable continuous protocol is the balance of reaction concentration against pressure in the flow reactor. The resulting process enables access to intercepted acylketene scaffolds using volatile amine nucleophiles and has been demonstrated on the gram scale. Thermal gravimetric analysis was used to