A Unified Catalytic Asymmetric (4+1) and (5+1) Annulation Strategy to Access Chiral Spirooxindole‐Fused Oxacycles
作者:Min Gao、Yanshu Luo、Qianlan Xu、Yukun Zhao、Xiangnan Gong、Yuanzhi Xia、Lin Hu
DOI:10.1002/anie.202105282
日期:2021.9
A unified catalyticasymmetric (N+1) (N=4, 5) annulation reaction of oxindoles with bifunctional peroxides has been achieved in the presence of a chiral phase-transfer catalyst (PTC). This general strategy utilizes peroxides as unique bielectrophilic four- or five-atom synthons to participate in the C−C and the subsequent umpolung C−O bond-forming reactions with one-carbon unit nucleophiles, thus providing
在手性相转移催化剂 (PTC) 的存在下,已经实现了羟吲哚与双官能过氧化物的统一催化不对称 ( N +1) ( N =4, 5) 环化反应。这种通用策略利用过氧化物作为独特的双亲电四原子或五原子合成子参与 C−C 和随后与单碳单元亲核试剂的 umpolung C−O 键形成反应,从而提供了一种独特的方法来获得有价值的手性螺吲哚-四氢呋喃和-四氢吡喃在温和条件下具有良好的产率和高对映选择性。进行 DFT 计算以合理化高对映选择性的起源。还证明了所得产物的克级合成和合成效用。
Synthesis of Substituted β-Styrylmalonates by Sequential Isomerization of 2-Arylcyclopropane-1,1-dicarboxylates and (2-Arylethylidene)malonates
作者:Roman A. Novikov、Yury V. Tomilov、Denis D. Borisov、Grigorii R. Chermashentsev
DOI:10.1055/a-1348-4311
日期:2021.7
A method has been developed for the synthesis of substituted β-styrylmalonates by conversion of 2-arylcyclopropane-1,1-dicarboxylates (ACDCs) in the presence of gallium trichloride into the corresponding 1,2-zwitterionic intermediates or (2-arylethylidene)malonates, followed by treatment with pyridine at room temperature leading to an isomerization of the emerging double bond. This method allows
There are provided compounds of the formula (I) wherein X, Y, R1, R2, R3, R3, R4, R5, R6 and R7 are as described herein and enantiomers and pharmaceutically acceptable salts and esters thereof. The compounds are useful as anticancer agents.
Solid catalyst component for olefin polymerization, catalyst for olefin polymerization, and method for producing olefin polymer
申请人:TOHO TITANIUM CO., LTD.
公开号:US11192965B2
公开(公告)日:2021-12-07
Provided is a solid catalyst component for olefin polymerization comprising an electron-donating compound other than a phthalate, the solid catalyst component being equal in the olefin-polymerizing activity and in the primary physical properties of the resulting polymer such as stereoregularity and molecular weight distribution to those with use of a phthalate as an electron-donating compound. A solid catalyst component for olefin polymerization comprises a magnesium atom, a titanium atom, a halogen atom, an ester compound (A) represented by a general formula (1) and a diester compound (B) represented by a general formula (2), wherein
a ratio represented by the following expression:
(content (mass %) of ester compound (A)/content (mass %) of diester compound (B))
is 0.05 to 50.
Asymmetric Michael reaction of lithiated trifluoroacetone SAMP-hydrazone with alkylidenemalonates gave addition products stereoselectively. Hydrolyzed enantiomerically pure ketoacids were cyclized to dihydropyridinones. N-lodopropylation followed by radical cyclization gave optically active trifluoromethylated indolizidinones stereoselectively.