Highly Enantioselective, Intermolecular Hydroamination of Allenyl Esters Catalyzed by Bifunctional Phosphinothioureas
摘要:
Bifunctional phosphinothiourea catalysts have been developed successfully for the highly regio- and enantioselective gamma-hydroamination of allenyl and propargyl esters with N-methoxy carbamate nucleophiles to yield alpha,beta-unsaturated gamma-amino acid ester products. In the case of propargyl ester substrates, the reaction proceeds through reversible phosphinothiourea-catalyzed isomerization to the corresponding allenyl ester. The high enantioselectivity of the process is attributed to a cooperative conjugate addition of a thiourea-bound carbamate anion to a vinyl phosphonium ion resulting from covalent activation of the allenyl ester substrate.
Design, synthesis and application of a new type of bifunctional Le-Phos in highly enantioselective γ-addition reactions of N-centered nucleophiles to allenoates
作者:Haile Qiu、Xiaofeng Chen、Junliang Zhang
DOI:10.1039/c9sc04073k
日期:——
A novel class of bifunctional cyclic phosphine catalysts (Le-Phos) is reported, which showed good performances in enantioselective γ-addition reactions of N-centered nucleophiles and allenoates under mild conditions.
Multicomponent Reaction to Construct Spirocyclic Oxindoles with a Michael (Triple Michael)/Cyclization Cascade Sequence as the Key Step
作者:Jian Li、Ning Wang、Chunju Li、Xueshun Jia
DOI:10.1002/chem.201104071
日期:2012.7.27
new strategy to access highly unusual tricyclic oxindoles. From a synthetic point of view, this protocol is very interesting considering the high level of complexity reached in one step. The mechanism is thought to proceed by a tripleMichael/cyclization process by using allenoate as a three carbon atom component (3 C). Furthermore, multicomponentreaction with γ‐substituted allenoate also results in
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
Nucleophilic phosphine-catalyzed [3+2] cycloaddition of allenes with N-(thio)phosphoryl imines and acidic methanolysis of adducts N-(thio)phosphoryl 3-pyrrolines: a facile synthesis of free amine 3-pyrrolines
作者:Bo Zhang、Zhengrong He、Silong Xu、Guiping Wu、Zhengjie He
DOI:10.1016/j.tet.2008.07.075
日期:2008.9
In this report, the dipolarophile imines with easily removable activating group O,O-diethyl(thio)phosphoryl have been investigated in the nucleophilic phosphine-catalyzed [3+2] cycloadditionreaction of electron-deficient allenes. Under the catalysis of a tertiary phosphine, N-(thio)phosphorylimines readily undergo the [3+2] cycloadditionreaction with ethyl 2,3-butadienoate or ethyl 2,3-pentadienoate
Regioselective [1N+2C+2C] Assembly of Fully Decorated Pyrroles from Primary Amines, 1,2-Diaza-1,3-dienes, and 2,3-Allenoates
作者:Francesca R. Perrulli、Gianfranco Favi、Lucia De Crescentini、Orazio A. Attanasi、Stefania Santeusanio、Fabio Mantellini
DOI:10.1002/ejoc.201501017
日期:2015.11
A mild, sequential multicomponent reaction strategy for the regioselective synthesis of functionalized pentasubstituted pyrrolesfrom readily accessible primaryamines, 1,2-diaza-1,3-dienes, and 2,3-allenoates, has been developed. The process allows a [1N+2C+2C] annulation to be achieved through two sequential hydroamination reactions followed by an enamine-carbocyclization. Moreover, allenoates, as