Selenium-Containing Heterocycles. Synthesis and Reactions of 2-Amino-4,5,6,7-tetrahydro-1-benzoselenophene-3-carbonitrile with Anticipated Biological Activity
Sterically Demanding Oxidative Amidation of α-Substituted Malononitriles with Amines Using O<sub>2</sub>
作者:Jing Li、Martin J. Lear、Yujiro Hayashi
DOI:10.1002/anie.201603399
日期:2016.7.25
An efficient amidation method between readily available 1,1-dicyanoalkanes and either chiral or nonchiral amines was realized simply with molecular oxygen and a carbonate base. This oxidative protocol can be applied to both sterically and electronically challenging substrates in a highly chemoselective, practical, and rapid manner. The use of cyclopropyl and thioether substrates support the radical
<i>S</i>-((Phenylsulfonyl)difluoromethyl)thiophenium Salts: Carbon-Selective Electrophilic Difluoromethylation of β-Ketoesters, β-Diketones, and Dicyanoalkylidenes
S‐((Phenylsulfonyl)difluoromethyl)thiopheniumsalts were designed and prepared by a triflic acid catalyzed intramolecular cyclization of ortho‐ethynyl aryldifluoromethyl sulfanes. The thiopheniumsalts were found to be efficient as electrophilic difluoromehtylating reagents for introduction of a CF2H group to sp3‐hybridized carbon nucleophiles such as of β‐ketoesters and dicyanoalkylidenes. The (p
S -((苯磺酰基)二氟甲基)噻吩盐是通过三氟甲磺酸催化邻乙炔基芳基二氟甲基硫烷的分子内环化反应而设计和制备的。发现噻吩盐作为将CF 2 H基团引入sp 3杂交的碳亲核试剂(如β-酮酸酯和二氰基亚烷基)的亲电子二氟甲基化试剂非常有效。的(苯磺酰基)二氟甲基可容易地转化为CF 2温和反应条件下小时。在双(金鸡纳)生物碱的存在下也实现了对映选择性亲电二氟甲基化。
Molybdenum carbide as an efficient and durable catalyst for aqueous Knoevenagel condensation
作者:Mina Tavakolian、Mohammad Mahdi Najafpour
DOI:10.1039/c9nj04647j
日期:——
and benign catalysts were used for the Knoevenagelcondensation reaction. Among the compounds (Mo2C, MoS2, MoB, MoSi2), molybdenum carbide showed efficient performance for the Knoevenagelcondensation in aqueous media at room temperature, affording the corresponding products in high yields within a short reaction time. Notably, using this commercially available heterogeneous catalyst, the deaceta
By employing triethylamine as a catalyst, [3 + 2] coupling‐eliminationcascade of α,α‐dicyanoolefins with quinonemonoimines was realized. The reactions afforded various novelpterocarpenanalogues with generally moderate yields (up to 75%). In addition, a plausible reaction mechanism was proposed.
The first direct asymmetricvinylogousMannich (AVM) reaction of alpha,alpha-dicyanoolefins and N-Boc aldimines was described promoted by a simple chiral bifunctional thiourea-tertairy amine organocatalyst. The reaction was highlyefficient (S/C up to 1000) and regio-, stereoselective (generally >99% de, 96 to >99.5% ee) at room temperature for a broad array of substrates. Enantiomerically pure delta-amino