Reported herein is a visible‐light‐mediated radical approach to the α‐alkylation of ketones. This method exploits the ability of a nucleophilic organocatalyst to generate radicals upon SN2‐based activation of alkyl halides and blue light irradiation. The resulting open‐shell intermediates are then intercepted by weakly nucleophilic silyl enol ethers, which would be unable to directly attack the alkyl
Samarium diiodide is a catalyst for the reaction of cyclic and acyclic tert-butyldimethylsilyl enoxysilanes with chelating imines. Reaction products are isolated as β-aminoenoxysilanes instead of β-aminoketones as previously observed with the corresponding trimethylsilyl enoxysilanes. Several mechanistic pathways are discussed.
Boron Trifluoride-Mediated Cycloaddition of 3-Bromotetrazine and Silyl Enol Ethers: Synthesis of 3-Bromo-pyridazines
作者:Simon D. Schnell、Jorge A. González、Jan Sklyaruk、Anthony Linden、Karl Gademann
DOI:10.1021/acs.joc.1c01384
日期:2021.9.3
regiocontrol remains difficult. We achieved the Lewis acid-mediated inverse electron demand Diels–Alder reaction between 3-monosubstituted s-tetrazine and silylenolethers and obtained functionalized pyridazines. In the case of 1-monosubstituted silylenolethers, exclusive regioselectivity was observed. Downstream functionalization of the resulting 3-bromo-pyridazines was demonstrated utilizing several cross-coupling
Copper-Catalyzed Fluoroolefination of Silyl Enol Ethers and Ketones toward the Synthesis of β-Fluoroenones
作者:Yanlin Li、Jing Liu、Shuang Zhao、Xuzhao Du、Minjie Guo、Wentao Zhao、Xiangyang Tang、Guangwei Wang
DOI:10.1021/acs.orglett.7b03700
日期:2018.2.16
A general and facile synthetic method for β-fluoroenones from silylenolethers or ketones, with a copper–amine catalyst system, has been developed. The reaction proceeded by a tandem process of difluoroalkylation–hydrolysis–dehydrofluorination. This method is characterized by high yields, excellent Z/E ratios, a low-cost catalyst, and a broad substrate scope. The synthetic potential of β-fluoroenones
α,β-Unsaturated ketones and aldehydes have been synthesized from their corresponding silyl enol ethers in a straightforward protocol involving a visible-light promoted organocatalytic, aerobic oxidation reaction. A cheap organic dye was used catalytically in these reactions as the photosensitizer.