A chiral N-heterocyclic carbene (NHC)-catalyzed [4 + 2] annulation of γ-chloroenals and α-arylidene pyrazolinones was developed in the absence of expensive oxidants. The reaction proceeds smoothly via a vinyl enolate intermediate to afford spirocyclohexane pyrazolones in moderate to good yield (up to 86%) with high diastereoselectivities (up to 15:1 dr) and excellent enantioselectivities (up to >99%
Organocatalytic asymmetric one-pot sequential reaction: synthesis of highly substituted spirocyclohexanepyrazolones with six contiguous stereogenic carbons
An atom-economical synthesis of chiral polyfunctionalized spiropyrazolone derivatives based on the development of a new organocatalytic enantioselective one-pot sequential Michael/Michael/Aldol reaction of 1,3-dicarbonyl compounds with unsaturated pyrazolones and α,β-unsaturated aldehydes has been developed. The notable features of this one-pot sequential process include the generation of up to six
基于新的1,3-二羰基化合物与不饱和吡唑啉酮和α,β-不饱和醛类的有机催化对映选择性一锅顺序Michael / Michael / Aldol反应的开发,开发了一种手性多官能螺并吡咯烷酮衍生物的原子经济合成方法。这种一锅法连续过程的显着特征包括最多生成六个连续的立体碳中心,包括一个具有高对映选择性(高达95%ee)和出色的非对映选择性(> 99:1 dr)的四级立体中心和五个三级立体中心。
Highly enantioselective cascade synthesis of spiropyrazolones
作者:Alex Zea、Andrea-Nekane R. Alba、Andrea Mazzanti、Albert Moyano、Ramon Rios
DOI:10.1039/c1ob05753g
日期:——
An efficient synthesis of spiropyrazolones based on organocatalysis is described. The reaction between pyrazolones, enolizable aldehydes and enals is catalyzed by secondary amine catalysts and affords the final spiro compounds bearing four contiguous chiral centers in good yields and excellent diastereo- and enantioselectivities.
Aus 4‐Aryliden‐5‐pyrazolonen und Malondinitril werden in Gegenwart von Natriummethylat die Titelverbindungen erhalten.
在甲醇钠存在下,由 4-亚芳基-5-吡唑啉酮和丙二腈得到标题化合物。
Bisphosphine catalyzed sequential [3 + 2] cycloaddition and Michael addition of ynones with benzylidenepyrazolones <i>via</i> dual α′,α′-C(sp<sup>3</sup>)–H bifunctionalization to construct cyclopentanone-fused spiro-pyrazolones
作者:Jiayong Zhang、Zhiwei Miao
DOI:10.1039/c8ob02675k
日期:——
A bisphosphine-catalyzed sequential [3 + 2] cycloaddition and Michael addition reaction of ynones with benzylidenepyrazolones has been developed. Under the catalysis of DPPB [1,4-bis(diphenylphosphino)butane], the reaction proceeded smoothly to give spiro-[cyclopentanone] pyrazolone derivatives in moderate to good yields with good diastereoselectivities via sequential dual α′,α′-C(sp3)–H bifunctionalization