Rhodium(III)-catalyzed annulation of acetophenone O-acetyl oximes with allenoates was achieved, affording isoquinolines in good to excellent yields with high regioselectivities under redox-neutral conditions. Allenoates acted as the C2 synthons in the annulation reaction. The present synthetic methodology features good functional group tolerance and avoids metal salts as the external oxidants. The
Synthesis of Functionalized Chromene and Chroman Derivatives via Cesium Carbonate Promoted Formal [4 + 2] Annulation of 2′-Hydroxychalcones with Allenoates
作者:Hossein Rouh、Yangxue Liu、Nandakumar Katakam、Lilian Pham、Yi-Long Zhu、Guigen Li
DOI:10.1021/acs.joc.8b02627
日期:2018.12.21
A new strategy has been established for the synthesis of functionalized chromene and chroman derivatives via a Cs2CO3-catalyzed domino addition of 2′-hydroxychalcone derivatives with allenoates, which can serve as a general avenue for the construction of multireplaced chromene derivatives. Chemoselectivity of this synthesis was found to depend on substituents on substrates. Good to excellent yields
已经建立了通过Cs 2 CO 3催化的2'-羟基查耳酮衍生物与烯丙酸酯的多米诺加成来合成官能化的色烯和苯并二氢吡喃衍生物的新策略,其可以用作构建多取代的色烯衍生物的一般途径。发现该合成的化学选择性取决于底物上的取代基。在简单和温和的条件下,在室温下获得了良好的优良收率。
Allenoate Prenucleophiles: A Triply Diastereoselective Approach to β-Hydroxy Esters Containing All-Carbon α-Quaternary Centers
作者:Samantha L. Maki、Pradip Maity、Shannon Dougherty、Jennifer Johns、Salvatore D. Lepore
DOI:10.1021/acs.orglett.9b02930
日期:2019.10.4
additions to a wide range of aldehydes in high regio- and diastereoselectivities leading to products containing an all-carbon quaternary center bearing an α-vinyl group that was installed with high selectivity for the Z-geometry. An aldol product was also converted to an indanone offering a new route to this important compound class. Product triple diastereoselectivity has been rationalized using a concerted
PBu<sub>3</sub>-Mediated Vinylogous Wittig Reaction of α-Methyl Allenoates with Aldehydes and Mechanistic Investigations
作者:Silong Xu、Rongshun Chen、Zhengjie He
DOI:10.1021/jo201466k
日期:2011.9.16
A highly stereoselective PBu3-mediated vinylogous Wittigolefination between α-methyl allenoates and a variety of aldehydes is presented as the first example of a practical and synthetically useful vinylogous Wittig reaction. Mechanistic experiments including deuterium-labeling, intermediate entrapment, and NMR monitoring have been deliberately conducted. On the basis of mechanistic investigations
Divergent, Enantioselective Synthesis of Pyrroles, 3<i>H</i>
-Pyrroles and Bicyclic Imidazolines by Ag- or P-Catalyzed [3+2] Cycloaddition of Allenoates with Activated Isocyanides
The divergent, stereoselective formal [3+2] cycloadditions of allenoates with activated isocyanides catalyzed by silver or phosphine‐based catalysts were investigated. Silver catalysis is capable of delivering a range of 3H‐pyrroles in high stereoselectivities. These enantioenriched heterocycles can either undergo sequential cyclisation with isocyanoacetates to deliver unprecedented bicyclic imidazolines