Asymmetric Construction of Spiropyrazolone Skeletons <i>via</i>
Amine-Catalyzed [3+3] Annulation
作者:Hai-Jun Leng、Qing-Zhu Li、Rong Zeng、Qing-Song Dai、Hong-Ping Zhu、Yue Liu、Wei Huang、Bo Han、Jun-Long Li
DOI:10.1002/adsc.201701035
日期:2018.1.17
Here we report a secondary amine‐catalyzed, highly enantioselective [3+3] cyclization reaction of α‐alkylidene pyrazolinones and α,β‐unsaturated aldehydes, which facilely delivers a variety of enantioenriched spiropyrazolones showing structural and stereochemical complexity. The reaction uses an iminium ion activation strategy to activate both the β‐ and ipso‐positions of the enals as dielectrophilic
Catalytic Diastereo- and Enantioselective Vinylogous Mannich Reaction of Alkylidenepyrazolones to Isatin-Derived Ketimines
作者:Laura Carceller-Ferrer、Carlos Vila、Gonzalo Blay、M. Carmen Muñoz、José R. Pedro
DOI:10.1021/acs.orglett.1c02571
日期:2021.10.1
A valuable organocatalytic vinylogous Mannich reaction between alkylidenepyrazolones and isatin-derived ketimines has been successfully established. Squaramide organocatalyst, prepared from quinine, catalyzed the diastereo- and enantioselective vinylogous Mannich addition, affording a range of aminooxindole-pyrazolone adducts (24 examples) with excellent outcomes: up to 98% yield with complete diastereoselectivity
亚烷基吡唑啉酮和靛红衍生的酮亚胺之间有价值的有机催化乙烯基曼尼希反应已经成功建立。由奎宁制备的方酸酰胺有机催化剂催化非对映选择性和对映选择性乙烯基曼尼希加成,提供一系列氨基吲哚-吡唑啉酮加合物(24 个例子),结果优异:高达 98% 的收率,完全非对映选择性和出色的对映选择性(高达 99% ee )。此外,使用手性吡唑啉酮-羟吲哚加合物进行了不同的合成转化。
Catalytic Diastereo- and Enantioselective Synthesis of Tertiary Trifluoromethyl Carbinols through a Vinylogous Aldol Reaction of Alkylidenepyrazolones with Trifluoromethyl Ketones
作者:Laura Carceller-Ferrer、Aleix González del Campo、Carlos Vila、Gonzalo Blay、M. Carmen Muñoz、José R. Pedro
DOI:10.1021/acs.joc.1c02817
日期:2022.4.1
trifluoromethylarylketone providing highly functionalized trifluoromethyl alcohols with moderate yields, excellent diastereoselectivity, and moderate to good enantioselectivity. Experiments monitoring the conversion by 1H NMR and the enantiomeric excess by HPLC with the reaction time showed that full conversion of the starting materials is not achieved and that the enantiomeric excess decreases upon extended times
提出了亚烷基吡唑啉酮和三氟甲基酮之间的非对映和对映选择性有机催化羟醛反应,生成带有三氟甲基的手性叔醇。该方法基于使用双功能有机催化剂来活化亚烷基吡唑啉酮亲核试剂的γ-氢原子和三氟甲基芳基酮的羰基,从而提供具有中等产率、优异的非对映选择性和中等至良好的对映选择性的高度官能化的三氟甲醇。通过1 H NMR 监测转化率并通过 HPLC 随反应时间监测对映体过量的实验表明,未实现起始原料的完全转化,并且对映体过量随着时间的延长而减少,这可能是由于反应的可逆性。
Highly Chemoselective [2+1] Annulation of α-Alkylidene Pyrazolones with α-Bromonitroalkenes: Synthesis of Pyrazolone-Based Vinylcyclopropanes and Computational Studies
作者:Ya-Jun Zhong、Ting Qi、Yan-Ling Ji、Hua Huang、Xiang Zhang、Hai-Jun Leng、Cheng Peng、Jun-Long Li、Bo Han
DOI:10.1021/acs.joc.0c02674
日期:2021.2.5
A highly chemoselective [2+1] annulation of α-alkylidene pyrazolones with α-bromonitroalkenes has been achieved undermildconditions. α-Alkylidene pyrazolones were unprecedentedly used as a C1 synthon to participate in annulation reactions, providing access to diverse vinylcyclopropane-based pyrazolone products. In addition, a spectrum of pharmaceutically interesting pyrazole-fused pyranone oximes
Michael–aldol dominoreaction between α-arylidene pyrazolinones and β,γ-unsaturated-α-ketoesters catalyzed by a chiral N,N′-dioxide-ScIII complex in aqueous media has been established. A variety of spirocyclohexene pyrazolones with three stereocenters including vicinal tetrasubstituted stereocenters were obtained in excellent yields with good diastereoselectivities and enantioselectivities. A retro-aldol