Rhodium-Catalyzed Asymmetric Conjugate Alkynylation/Aldol Cyclization Cascade for the Formation of α-Propargyl-β-hydroxyketones
作者:Ken-Loon Choo、Mark Lautens
DOI:10.1021/acs.orglett.8b00153
日期:2018.3.2
A rhodium-catalyzedconjugatealkynylation/aldol cyclization cascade was developed. Densely functionalized cyclic α-propargyl-β-hydroxyketones were synthesized with simultaneous formation of a C(sp)–C(sp3) bond, a C(sp3)–C(sp3) bond, as well as three new contiguous stereocenters. The transformation was achieved with excellent enantio- and diastereoselectivities using BINAP as the ligand. The synthetic
The copper-catalyzed [4 + 2] annulation of α,β-unsaturated ketoximeacetates with 1,3-dicarbonyl compounds for the synthesis of three classes of structurally diverse pyridines has been developed. This method employs 1,3-dicarbonyl compounds as C2 synthons and enables the synthesis of multifunctionalized pyridines with diverse electron-withdrawing groups in moderate to good yields. The mechanistic investigation
Tandem Wittig Reaction–Ring Contraction of Cyclobutanes: A Route to Functionalized Cyclopropanecarbaldehydes
作者:Federico Cuccu、Lorenzo Serusi、Alberto Luridiana、Francesco Secci、Pierluigi Caboni、David J. Aitken、Angelo Frongia
DOI:10.1021/acs.orglett.9b02690
日期:2019.10.4
An original tandem reaction consisting of a Wittig reaction-ring contraction process between α-hydroxycyclobutanone and phosphonium ylides has been developed. Highly functionalized cyclopropanecarbaldehydes are obtained in good to high yield.
Catalyst‐free green synthesis and study of antioxidant activity of new pyrazole derivatives
作者:Navisa Tabarsaei、Naghmeh Faal Hamedani、Shahin Shafiee、Samira Khandan、Zinatossadat Hossaini
DOI:10.1002/jhet.4004
日期:2020.7
In this research, a novel procedure for the synthesis of pyrazole derivatives in excellent yields was studied using catalyst‐free multicomponent reaction of isoquinoline, activated acetylenic compounds, alkyl bromides, triphenylphosphine and hydrazine in water under ultrasonic irradiation at room temperature. The advantages of this procedure than to reported methods are short time of reaction, high
Rh(<scp>iii</scp>)-catalyzed diastereoselective cascade annulation of enone-tethered cyclohexadienones <i>via</i> C(sp<sup>2</sup>)–H bond activation
作者:Sandip B. Jadhav、Sundaram Maurya、N. Navaneetha、Rambabu Chegondi
DOI:10.1039/d1cc05941f
日期:——
highly diastereoselective arylative cyclization of enone-tethered cyclohexadienones via Rh(III)-catalyzed C–H activation of N-methoxybenzamides. This reaction proceeds through the formation of a five-membered rhodacycle followed by bis-Michael cascade annulation to access functionalized bicyclic scaffolds with four contiguous stereocenters with a broad substrate scope. These products have excellent functional
在此,我们报告了通过Rh( III ) 催化的N-甲氧基苯甲酰胺的C-H 活化对烯酮系环己二烯酮进行高度非对映选择性芳基化环化。该反应通过形成五元罗丹环进行,然后是双迈克尔级联环化,以访问具有广泛底物范围的具有四个连续立体中心的功能化双环支架。这些产品具有出色的功能手柄,允许进一步合成转化以增加结构复杂性。此外,还介绍了芳基化环化的机理研究和克级实验。