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。
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
DMAP Catalyzed Domino Rauhut–Currier Cyclization Reaction between Alkylidene Pyrazolones and Nitro-olefins: Access to Tetrahydropyrano[2,3-<i>c</i>]pyrazoles
作者:Nimisha Bania、Buddhadeb Mondal、Sounak Ghosh、Subhas Chandra Pan
DOI:10.1021/acs.joc.0c02871
日期:2021.3.5
Herein, we employ unsaturated pyrazolones in the Rauhut–Currier reaction for the first time. A domino Rauhut–Currier cyclization reaction has been developed between unsaturated pyrazolones and nitro-olefins. The trisubstituted tetrahydropyrano[2,3-c]pyrazoles were obtained in moderate to high yields with excellent diastereoselectivities. A few applications including a synthesis of disubstituted tetrahydropyrano[2
在本文中,我们首次在Rauhut-Currier反应中使用了不饱和吡唑啉酮。在不饱和吡唑啉酮和硝基烯烃之间发展了多米诺Rauhut-Currier环化反应。三取代四氢吡喃并[2,3- c ]吡唑以中等至高收率获得,具有非对映选择性。已经证明了包括合成二取代的四氢吡喃并[2,3- c ]吡唑在内的一些应用。还使用手性DMAP催化剂研究了该方法的初步催化不对称形式。
Asymmetric [4 + 2] Annulation Reactions Catalyzed by a Robust, Immobilized Isothiourea
作者:Shoulei Wang、Javier Izquierdo、Carles Rodríguez-Escrich、Miquel A. Pericàs
DOI:10.1021/acscatal.7b00360
日期:2017.4.7
A polystyrene-supported isothiourea (1a) behaves as a highly efficient organocatalyst in a variety of formal [4 + 2] cycloaddition reactions. The catalytic system has proven to be highly versatile, leading to six-membered heterocycles and spiro-heterocycles bearing an oxindole moiety in high yields and very high enantioselectivities (32 examples, including the previously unreported oxindole spiropyranopyrazolones
The Regiocontrollable Enantioselective Synthesis of Chiral Trifluoromethyl-Containing Spiro-Pyrrolidine-Pyrazolone Compounds via Amino-Regulated 1,3-Proton Migration Reaction
as catalyst, the 1,3-dipolar cycloaddition of α,β-unsaturated pyrazolone with diethyl2-((2,2,2-trifluoroethyl)imino) malonate offered adducts in excellent yields, dr, and ee. While the cyclohexanediamine-derived squaramide was employed, the reaction afforded a series of structure isomers through a switched umpolung reaction.