Ag-Catalyzed Insertion of Alkynyl Carbenes into C–C Bonds of β-Ketocarbonyls: A Formal C(sp<sup>2</sup>) Insertion
作者:Yongquan Ning、Qingmin Song、Paramasivam Sivaguru、Lizuo Wu、Edward A. Anderson、Xihe Bi
DOI:10.1021/acs.orglett.1c04081
日期:2022.1.21
Here we report a silver-catalyzed alkynyl carbene insertion into β-ketocarbonyls using alkynyl N-nosylhydrazones as alkynyl carbene precursors, which provides access to trisubstituted allenyl ketones. This reaction represents the first example of an alkynyl carbene insertion into a C–C σ bond, affording products homologated with an sp2 carbon center. The products are useful substrates for further transformations
Catalyst-Dependent Chemoselective Formal Insertion of Diazo Compounds into C−C or C−H Bonds of 1,3-Dicarbonyl Compounds
作者:Zhaohong Liu、Paramasivam Sivaguru、Giuseppe Zanoni、Edward A. Anderson、Xihe Bi
DOI:10.1002/anie.201802834
日期:2018.7.16
one‐carbon insertion of diazo compounds into the C−C or C−H bonds of 1,3‐dicarbonyl species is reported. In the presence of silver(I) triflate, diazo insertion into the C(=O)−C bond of the 1,3‐dicarbonyl substrate leads to a 1,4‐dicarbonyl product containing an all‐carbon α‐quaternary center. This reaction constitutes the first example of an insertion of diazo‐derived carbenoids into acyclic C−C bonds. When
Asymmetric Hydrogenation of 2,4-Disubstituted 1,5-Benzodiazepines Using Cationic Ruthenium Diamine Catalysts: An Unusual Achiral Counteranion Induced Reversal of Enantioselectivity
作者:Zi-Yuan Ding、Fei Chen、Jie Qin、Yan-Mei He、Qing-Hua Fan
DOI:10.1002/anie.201200309
日期:2012.6.4
highly enantioselectivehydrogenation of 2,4‐disubstituted 1,5‐benzodiazepines using chiral cationicrutheniumdiaminecatalysts (R,R)‐1 has been developed (see scheme; BArF=tetrakis(3,5‐bistrifluoromethylphenyl)borate). Either enantiomer of 2,4‐diaryl‐2,3,4,5‐tetrahydro‐1H‐benzodiazepine derivatives could be obtained by using the same enantiomer of ligand but in the presence of a different achiral counteranion
Isopropylmagnesium chloride-promoted unilateral addition of Grignard reagents to β-diketones: one-pot syntheses of β-tertiary hydroxyl ketones or 3-substituted cyclic-2-enones
作者:Rui Yuan、Dan Zhao、Li-Yuan Zhang、Xiang Pan、Yan Yang、Pei Wang、Hong-Feng Li、Chao-Shan Da
DOI:10.1039/c5ob02072g
日期:——
unilateral additions of Grignardreagents to acyclic or cyclic β-diketones were effectively promoted by sub-stoichiometric amounts of i-PrMgCl to afford β-tertiary hydroxyl ketones or 3-substituted cyclic-2-enones, respectively. Also, the addition of Grignardreagents to acyclic β-diketones followed by a reaction with cyclic β-diketones in a one-pot process was put forward. The reaction mechanism was discussed