Stereospecific Electrophilic Fluorocyclization of α,β-Unsaturated Amides with Selectfluor
作者:Haiyang Fei、Zheyuan Xu、Hongmiao Wu、Lin Zhu、Hitesh B. Jalani、Guigen Li、Yao Fu、Hongjian Lu
DOI:10.1021/acs.orglett.0c00620
日期:2020.4.3
An efficient fluorocyclization of α,β-unsaturated amides through a formal halocyclization process is developed. The reaction proceeds undertransition-metal-freeconditions and leads to the formation of fluorinated oxazolidine-2,4-diones with excellent regio- and diastereoselectivity. The evaluation of the reaction mechanism based on preliminary experiments and density functional theory calculations
Manganese(I) Catalyzed α-Alkenylation of Amides Using Alcohols with Liberation of Hydrogen and Water
作者:Biplab Keshari Pandia、Chidambaram Gunanathan
DOI:10.1021/acs.joc.1c00685
日期:2021.8.6
Herein, unprecedented manganese-catalyzed direct α-alkenylation of amides using alcohols is reported. Aryl amides are reacted with diverse primary alcohols, which provided the α,β-unsaturated amides in moderate to good yields with excellent selectivity. Mechanistic studies indicate that Mn(I) catalyst oxidizes the alcohols to their corresponding aldehydes and also plays an important role in efficient
Titanium-Promoted Cross-Coupling for the Selective Synthesis of Polysubstituted, Conjugated Amides
作者:Vinoth Kumar Chenniappan、Ronald J. Rahaim
DOI:10.1021/acs.orglett.6b02537
日期:2016.10.7
α,β-Unsaturated amides are important buildingblocks and are key structural elements in a number of biologically active natural products. Despite their importance and prevalence, few methods exist to prepare conjugated amides directly and modularly. To address this gap, a titanium-promoted coupling of alkynes and isocyanates has been developed. The method is highly stereoselective, producing only the
Stereoselective Formal Hydroamidation of Si-Substituted Arylacetylenes with DIBAL-H and Isocyanates: Synthesis of (<i>E</i>)- and (<i>Z</i>)-α-Silyl-α,β-unsaturated Amides
stereoselective method for the synthesis of (E)- and (Z)-α-silyl-α,β-unsaturatedamides and its synthetic applications are presented herein. The solvent-controlled hydroaluminations of Si-substituted alkynes with DIBAL-H generate diastereomerically enriched alkenylaluminum reagents that are directly reacted with isocyanates at ambient temperature to afford α-silyl-α,β-unsaturatedamides in high yields with retained
Strike while the iron is hot! A BF3‐mediated formal [2+2] cycloaddition between (1‐alkynyl)iron complexes and aromatic aldehyde imines occurs, which is followed by ring‐opening of the initially formed azacyclobutenes to yield (2‐alkenyl‐1‐imino)iron complexes (see scheme). The resulting iron complexes undergo deferric substitution reactions with water under oxidative conditions to afford the corresponding