The copper-catalyzed asymmetric [3 + 3] annulation of ethynyl benzoxazinanones with pyrazolones has been achieved, providing simple access to 1,4-dihydropyrano[2,3-c]pyrazole derivatives in moderate to excellent yields with excellent enantioselectivities (up to 99% ee). Compared with previous annulation reactions of copper–allenylidenes from ethynyl benzoxazinanones, the current reaction fused the
乙炔基苯并恶嗪酮与吡唑啉酮的铜催化不对称环化[3 + 3]已实现,可轻松获得1,4-二氢吡喃并[2,3- c ]吡唑衍生物,且产率中等至优异,对映选择性极佳(高达99 %ee)。与以前的乙炔基苯并恶嗪酮的铜-亚烯基环化反应相比,当前反应将炔丙基部分的三个碳原子融合成杂环骨架。
One-Pot Asymmetric Synthesis of Spiropyrazolone-Linked Cyclopropanes and Benzofurans through a General Michael Addition/Chlorination/Nucleophilic Substitution Sequence
A sequential and general strategy has been successfully developed for the synthesis of spiropyrazolone scaffolds. This intriguing transformation of the asymmetric multicomponent catalysis process was realized with the combination of Michael addition/chlorination/nucleophilic substitution in a one-pot sequence, giving rise to a series of spiropyrazolones with fully substituted cyclopropanes and spi
An asymmetricaddition of arylboronicacids to pyrazolinone ketimines is reported using palladium/chiral N,N′-disulfonyl bisimidazoline (Bim) catalytic system, producing 25 examples of enantioenriched 4-amino-5-pyrazolones bearing one quaternary carbon stereocenter with 60–91% yields and 81–98% ee. The reaction demonstrates remarkable compatibility regarding pyrazolinone ketimines and arylboronic acids
Asymmetric Organocatalytic [4 + 1] Annulations Involving a Polarity Reversal Process: A Tandem Catalytic Approach to Highly Functionalized Spiropyrazolone Derivatives
A tandemcatalytic strategy for the asymmetric synthesis of spirocyclopentanone pyrazolones bearing threecontiguousstereocenters and two quaternary carbons with good stereoselectivities has been developed. This strategy, using pyrazolones as efficient C1 synthons and involving a polarity reversal process, not only overcame the energy barrier of the dearomatization process but also avoided nucleophilic
Enantioselective Synthesis of Spirorhodanine-Pyran Derivatives via Organocatalytic [3 + 3] Annulation Reactions between Pyrazolones and Rhodanine-Derived Ketoesters
A series of novel biselectrophilic β,γ-unsaturatedα-ketoesters were designed and synthesized from rhodanine. Under the catalysis of chiral squaramides, the enantioselective [3 + 3] annulation reaction of these novel ketoesters with pyrazolones was developed. This reaction offers an efficient method for the synthesis of chiral 2'-thioxo-5,6-dihydrospiro[pyrano[2,3-c]pyrazole-4,5'-thiazolidin]-4'-ones