The catalytic enantioselective diorganozinc additions to cyclic diketones including pyrazolin‐4,5‐diones and isatins have been developed. In the presence of morpholine‐containing chiral amino alcohol ligand, the corresponding chiral cyclic tertiary alcohols were produced in good to excellent yields (up to 97 %) and enantioselectivities (up to 95 % ee). The notable feature of this protocol includes
Synthesis of Selenopyrano[2,3-c]pyrazol-4(1H)-ones and Their C–H Activation
作者:Hitesh B. Jalani、Jin-Hyun Jeong、In-Hui Choi
DOI:10.1055/a-1296-8835
日期:2021.2
3-c]pyrazol-4(1H)-ones and their aryl derivatives for the first time using seleno-pyran ring formation via an in situ generated selenide reacting directly with α-halo-β-ynones bearing substituted pyrazoles to provide concomitant selenopyrano[2,3-c]pyrazol-4(1H)-ones. Subsequent direct C–H arylation of the later compounds effected by palladium catalyzed Heck reaction enables the incorporation of arene
preparation of a seven-membered O-heterocyclic ring is presented, which is an achievement of methyl and carbonyl group reactivity of 3-methyl-5-pyrazolones to forge the Csp3–O bond. This novel protocol provides a straightforward and efficient access to structurally diverse fused O-heterocycles through an iodine-catalyzed iodination/Kornblum oxidation/oxidativecoupling/C–O bond formation cascade reaction. This
介绍了碘催化的催化形式[3 + 3 +1]环加成制备七元O杂环的方法,这是3-甲基-5-吡唑酮的甲基和羰基反应性的锻造。 C sp3 -O键。该新方案通过碘催化的碘化/ Kornblum氧化/氧化偶联/ C-O键形成级联反应,提供了直接有效地接触结构多样的稠合O杂环的方法。该方法证明了在空洞的同时实现3-甲基-5-吡唑啉酮中的甲基,亚甲基和羰基之间独特的反应性,以实现2,3-二氢氧杂环丁烷环的构建。此外,广泛的底物范围显示了优美的面向多样性的合成方法。
Highly Stereoselective Synthesis of Spiropyrazolones
作者:Andrea-Nekane R. Alba、Alex Zea、Guillem Valero、Teresa Calbet、Merce Font-Bardía、Andrea Mazzanti、Albert Moyano、Ramon Rios
DOI:10.1002/ejoc.201001452
日期:2011.3
The synthesis of spiro compounds through a Michael–Michael–aldol reaction is reported. The reaction affords spiropyrazolone derivatives in good yields, in almost diastereo- and enantiopure form, and is catalyzed by diphenylprolinol derivatives. The reaction showed strong nonlinear effects. Remarkably, when a catalyst with 70 % ee is used, the reaction still affords the final spiro compound in almost
报道了通过迈克尔-迈克尔-羟醛反应合成螺环化合物。该反应以良好的收率提供几乎非对映纯和对映纯形式的螺吡唑啉酮衍生物,并由二苯基脯氨醇衍生物催化。该反应表现出很强的非线性效应。值得注意的是,当使用 70% ee 的催化剂时,反应仍然提供几乎非对映纯和对映纯形式的最终螺环化合物。
Asymmetric, Three-Component, One-Pot Synthesis of Spiropyrazolones and 2,5-Chromenediones from Aldol Condensation/NHC-Catalyzed Annulation Reactions
A novel one‐pot, three‐component diastereo‐ and enantioselective synthesis of spiropyrazolones has been developed involving the aldol condensation of an enal to generate α,β‐unsaturated pyrazolones, which react with a second equivalent of enal through an N‐heterocyclic carbene (NHC)‐catalyzed [3+2] annulation. The desired spirocyclopentane pyrazolones are obtained in moderate to good yields and good