the corresponding cyclohexenones 4 with a remote chiral all‐carbon quaternary center at the γ position is described. Chiral rhodium–bis(oxazolinyl)phenyl complexes 1 were effective catalysts for this transformation. This catalytic system was extended to the asymmetric transformation of spirocarbocyclic cyclohexadienones 5 to give the corresponding products 6 with highenantiomeric ratios.
Asymmetric organocatalytic desymmetrization of 4,4-disubstituted cyclohexadienones at high pressure: a new powerful strategy for the synthesis of highly congested chiral cyclohexenones
A highly diastereoselective and enantioselective method for the asymmetric desymmetrization of 4,4-disubstituted cyclohexadienones using the Michael addition reaction of malonates under catalysis with the primary amine-thiourea conjugate catalyst and PPY at high pressure was developed.
Stereochemical Studies. XXVI. Asymmetric Synthesis using Proline Derivatives of optically Active Various 4, 4-Disubstituted 2-Cyclohexenones with Enamine Alkylation
作者:GENJI OTANI、SHUNICHI YAMADA
DOI:10.1248/cpb.21.2125
日期:——
Enamines III, prepared from some disubstituted acetaldehydes I and L-proline pyrrolidide (II), were alkylated with methyl vinyl ketone to generally afford optically active 4, 4-disubstituted 2-cyclohexenones V. This asymmetric synthesis is found to be widely applicable, their absolute configurations could be deduced by a comparison of the two substituents.
由一些二取代乙醛 I 和 L-脯氨酸吡咯烷酮 (II) 制备的烯胺 III 经甲基乙烯酮烷基化后,一般可得到具有光学活性的 4,4-二取代 2-环己烯酮 V。
Synthesis of <i>meta</i>-arylphenol derivatives <i>via</i> acid-promoted rearrangement of cyclohexadienones
作者:Hongyan Xie、Minxiang Zhang、Xueyu Fang、Zhaohua Yan、Hua Yao
DOI:10.1039/d3ob01363d
日期:——
A highly effective strategy for the synthesis of meta-arylphenol derivatives through the selective rearrangement of 4-alkyl-4-aryl-2,5-cyclohexadienones under metal-free conditions was developed, in which acid-promoted [1,2]-migration of the aryl group at C-4 occurred exclusively when the alkyl group at C-4 was a methyl group. Treatment of 4-methyl-4-aryl-2,5-cyclohexadienones with 37% HCl in Ac2O