Hydroformylation of alkynes is an underdeveloped atom-economic and redox-neutral method to prepare enals. Applying a new electron poor self-assembling ligand system provides the first general rhodium-catalyst for the chemo- and stereoselective hydroformylation of dialkyl- as well as diaryl-substituted alkynes to furnish enals in excellent chemo- and stereoselectivity.
Synthesis of stilbene analogues by one-pot oxidation-Wittig and oxidation-Wittig–Heck reaction
作者:Akeel S. Saiyed、Krupa N. Patel、Bola V. Kamath、Ashutosh V. Bedekar
DOI:10.1016/j.tetlet.2012.06.090
日期:2012.8
Synthesis of symmetrical (and unsymmetrical) stilbene derivatives is achieved by a combination of one-pot steps of Kornblum type oxidation of benzyl halide, its simultaneous in situ formation of phosphonium salt, and subsequently their Wittig reaction. In other variant it is oxidized to aldehyde, treated with ylide generated from phosphonium salt (CH3PPh3X) to give styrene, and subjected to Pd catalyzed
triplet energy was greatly improved, and then, it could markedly promote the efficient geometrical isomerization of alkenes from the E-isomer to the Z-isomer. Moreover, it was also effective for energy-transfer-mediated organometallic catalysis, which allowed realization of the cross-coupling of aryl bromides and carboxylic acids through efficient energy transfer from HiBRCP to nickel complexes. Thus, the
Electron Transfer to Benzenes by Photoactivated Neutral Organic Electron Donor Molecules
作者:Elise Cahard、Franziska Schoenebeck、Jean Garnier、Sylvain P. Y. Cutulic、Shengze Zhou、John A. Murphy
DOI:10.1002/anie.201200084
日期:2012.4.10
Powerful reduction reactions: Simple organic electron donors, composed solely of the elements carbon, hydrogen, and nitrogen, reduce ground‐state benzene rings to their radicalanions by electron transfer upon photoactivation (DMF=dimethylformamide).
Unsupported Nanoporous Gold Catalyst for Chemoselective Hydrogenation Reactions under Low Pressure: Effect of Residual Silver on the Reaction
作者:Balaram S. Takale、Xiujuan Feng、Ye Lu、Ming Bao、Tienan Jin、Taketoshi Minato、Yoshinori Yamamoto
DOI:10.1021/jacs.6b06569
日期:2016.8.17
observed for O2 oxidation. This marked contrast between H2 reduction and O2 oxidation is discussed. Further, Au>99Ag1NPore showed a high chemoselectivity toward reduction of terminal alkynes in the presence of internal alkynes which was not achieved using supported gold nanoparticle catalysts and other previously known methods. Reductive amination, which has great significance in synthesis of amines due