Thermal Addition Reaction of Aroylketene with 1-Aryl-1-trimethylsilyloxyethylenes: Aromatic Substituent Effects of Aroylketene and Aryltrimethylsilyloxyethylene on Their Reactivity.
作者:Shlomy Arava、Jayprakash N. Kumar、Shimon Maksymenko、Mark A. Iron、Keshaba N. Parida、Peter Fristrup、Alex M. Szpilman
DOI:10.1002/anie.201610274
日期:2017.3.1
Enolonium species/iodo(III)enolates of carbonyl compounds have been suggested to be intermediates in a wide variety of hypervalent iodine induced chemical transformations of ketones, including α‐C−O, α‐C−N, α‐C−C, and α‐carbon–halide bond formation, but they have never been characterized. We report that these elusive umpoled enolates may be made as discrete species that are stable for several minutes
Thermal Addition Reaction of Aroylketene with 1-Aryl-1-trimethylsilyloxyethylenes: Aromatic Substituent Effects of Aroylketene and Aryltrimethylsilyloxyethylene on Their Reactivity.
The thermal addition reaction of various aroylketenes (C) generated by the thermolysis of 5-aryldioxofurans (A) to 1-aryl-1-trimethylsilyloxyethylenes gave 1, 5-diarylpentane-1, 3, 5-triones (D) and 2, 6-diaryl-4H-pyran-4-ones (E). The introduction of electron withdrawing substituents in the aroylketene and of electron donating substituents facilitated the addition reaction. The observed substituent effects and the reaction mechanism are interpreted in terms of molecular orbital analyses.
Various β-nitro ketones, including those bearing a β-tertiary carbon, were prepared from geminal bromonitroalkanes and trimethylsilyl enol ethers of a broad range of ketones by visiblelightphotoredoxcatalysis, which were then easily converted into β-amino ketones, 1,3-amino alcohols, α,β-unsaturated ketones, β-cyano ketones and γ-nitro ketones.