Highly Efficient Cs2CO3-Catalyzed 1,4-Addition of Me3SiCN to Enones with Water as the Additive
作者:Fu-Xue Chen、Jingya Yang、Yongbin Shen
DOI:10.1055/s-0029-1218653
日期:2010.4
A facile and efficient 1,4-addition of Me3SiCN to enones has been achieved with perfect regioselectivity using Cs2CO3 as catalyst. Thus, with 0.5 mol% of Cs2CO3 and 4 equivalents of H2O as the additive excellent yields (81-99%) of β-cyanoketones are obtained within one to five hours. Both aromatic and aliphatic enones are found suitable substrates for this protocol.
Cyano-borrowing reaction: nickel-catalyzed direct conversion of cyanohydrins and aldehydes/ketones to β-cyano ketone
作者:Zhao-Feng Li、Qian Li、Li-Qing Ren、Qing-Hua Li、Yun-Gui Peng、Tang-Lin Liu
DOI:10.1039/c9sc00640k
日期:——
nickel-catalyzed, high atom- and step-economical reaction of cyanohydrins with aldehydes or ketones via an unprecedented “cyano-borrowing reaction” has been developed. Cleavage of the C–CN bond of cyanohydrins followed by aldol condensation and conjugate addition of cyanide to α,β-unsaturated ketones proceeded to deliver a range of racemic β-cyano ketones with good to high yields. The practical procedure
Chiral Sodium Phosphate Catalyzed Enantioselective 1,4-Addition of TMSCN to Aromatic Enones
作者:Fu-Xue Chen、Jingya Yang、Shaoxiang Wu
DOI:10.1055/s-0030-1258817
日期:2010.11
A facile enantioselective 1,4-addition of TMSCN to aromatic enones has been developed using chiral sodium phosphate. Thus, in the presence of 20 mol% of sodium salt generated in situ from (R)-3,3′-di(1-adamantyl)-1,1′-binaphthyl-2,2′-diylphosphoric acid and NaOH, β-cyano ketones were obtained in high yield (86-96%) and up to 72% ee within three hours at 80 ËC in toluene.
Highly Efficient Syntheses of β-Cyanoketones via Conjugate Addition of Me3SiCN to Aromatic Enones
作者:Jingya Yang、Fuxue Chen
DOI:10.1002/cjoc.201090182
日期:——
An efficient 1,4‐addition of Me3SiCN to aromatic enones has been achieved with excellent yields (91% –99%) using CsF (1 mol%) as the catalyst and H2O (4 equiv.) as the additive in refluxing dioxane within 7 h. The perfect regioselectivity is proposed accounting from H2O‐facilitated reversion of the 1,2‐adduct in the presence of CsF and subsequent irreversible 1,4‐addition reaction.
Herein is reported an electrochemical procedure based on the Hydrogen Evolution Reaction of acetone cyanohydrin at a Pt cathode enabling the cyanation of α,β- unsaturated carbonyl and imines. Catalytic current, along with a correspondingly reduced quantity of supporting electrolyte, facilitates the scalability of the procedure, ensuring brief electrolysis times while maintaining a simple electrochemical