Oxone-promoted hydration of electron-deficient allenic esters and ketones into 1,3-dicarbonyl compounds
摘要:
A novel and mild protocol for the hydration of electron-deficient allenic esters and ketones into various 1,3-dicarbonyl compounds is described. The hydration of allenes promoted by oxone in DMF afforded the corresponding products in moderate to good yields. This work features the employment of only a catalytic amount of inexpensive and nontoxic solid reagent oxone (2KHSO(5)center dot KHSO4 center dot K2SO4), avoiding the utility of toxic metals or traditional Bronsted acids, in a green version of viewpoint. A possible reaction mechanism for this transformation is also primarily proposed. (C) 2015 Elsevier Ltd. All rights reserved.
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
Phosphine-Catalyzed Intermolecular Dienylation of Alkynoate with <i>para</i>-Quinone Methides
作者:Zefeng Song、Weijia Wang、Zhixin Liu、Yue Lu、De Wang
DOI:10.1021/acs.joc.1c00226
日期:2021.7.2
An interesting remote δ-C 1,6-addition and an isomerization cascade reaction for phosphine-catalyzed activated alkynes have been disclosed. The products featuring a functional diene and a 1,1-diaryl methyl motif have been obtained in moderate to good yields (30–86%) by applying para-quinone methides (p-QMs) and δ-substituted alkynoate with tributylphosphine (PnBu3) catalysis, along with high regioselectivity
已经公开了一种有趣的远程 δ-C 1,6-加成和膦催化的活化炔烃的异构化级联反应。通过应用对醌甲基化物 ( p -QMs) 和 δ-取代的炔酸酯与三丁基膦 (P n Bu 3 ) 催化,以及高区域选择性和立体选择性(dr > 20:1)。广泛的兼容底物(35 个示例),例如吲哚基、羟吲哚基、酯和肉桂基,扩展了该方法的实用性。还介绍了一种合理的机制及其一些应用。
Allene Carboxylates as Dipolarophiles in Rh-Catalyzed Carbonyl Ylide Cycloadditions
作者:Laxmidhar Rout、Andrewâ M. Harned
DOI:10.1002/chem.200902208
日期:2009.12.7
Face‐to‐face: Allenecarboxylates can serve as efficient dipolarophiles for Rh‐catalyzed carbonylylidecycloadditions (see scheme). The endo and exo products arise from cycloaddition on the same face of the allene, but opposite faces of the dipole. This facial selectivity results in the formation of two of the four possible diastereomers.
Telescoping Reactions with Trifluorodiazoethane-Derived Aza-Wittig Reagents and Allenyl esters
作者:Fa-Guang Zhang、Jun-Liang Zeng、Yi-Qiang Tian、Yan Zheng、Dominique Cahard、Jun-An Ma
DOI:10.1002/chem.201801171
日期:2018.5.28
developed for the novel functionalization of allenyl esters. First, new phosphazenes derived from trifluorodiazoethane and phosphines were generated and reacted with allenyl esters to give unexpected α‐iminophosphoranes through the creation of C=P, C=N, and C−H bonds at the α‐, β‐, and γ‐carbon atoms, respectively, of the allenyl esters. The α‐iminophosphoranes did not react with aldehydes in a classic Wittig
Phosphine-catalyzed domino reaction: a novel sequential [2+3] and [3+2] annulation reaction of γ-substituent allenoates to construct bicyclic[3, 3, 0]octene derivatives
作者:Erqing Li、You Huang
DOI:10.1039/c3cc47716a
日期:——
We have successfully developed a novel and efficient phosphine-catalyzed sequential [2+3] and [3+2] annulation reaction of gamma-substituent allenoates to construct bicyclic[3, 3, 0]octene derivatives. The protocol uses readily available gamma-substituent allenoates as the starting materials, inexpensive PBu3 as the catalyst, and the corresponding products were obtained in good to excellent yields