Reactivity of a propiolate dimer with nucleophiles and an efficient synthesis of dimethyl α-aminoadipate
摘要:
Ail enyne dimer (1) of methyl propiolate was reacted with amines to form dimethyl (E,E)-2-amino-2,4-hexacliene dioates with remarkable chemospecificity, regiospecificity, and sterecispecificity. This enyne was also reduced by Ph3P stereospecifically to form dimethyl (E,E)-muconic ester. Hydrogenation of the conjugated amino-diene led to an efficient production of dimethyl alpha-aminoadipate. A lactam of dimethyl alpha-aminoadipate was obtained in high yield by simply varying the hydrogenation conditions. (C) 2009 Elsevier Ltd. All rights reserved.
Multicomponent reactions of phosphines, enynedioates and benzylidene malononitriles generated highly substituted cyclopentenes through an unexpected phosphine α-addition-δ-evolvement of an anion pathway
Multicomponent reactions of phosphines, enynedioates and benzylidene malononitriles provide highly substituted syn-selective cyclopentenes appending the phosphorus ylide moiety in good yield with a diastereoselectivity of up to 100% through resonance-derived 1,5-dipolar species as the key intermediates, via the nucleophilic α(δ′)-attack of phosphines toward enynedioates followed by addition to benzylidene
Regioselective solvent-dependent benzannulation of conjugated enynes
作者:Florian Pünner、Gerhard Hilt
DOI:10.1039/c2cc30777d
日期:——
transformation of enynes under cobalt-catalysis leads to symmetrical benzannulation products in dichloromethane. In tetrahydrofuran the cobalt-catalysed reactions afforded the unprecedented unsymmetrical benzannulation products in moderate to good yields and good regioselectivities. In addition, cyclotrimerisation of the alkyne subunit can be realised when electron-deficient enynes are applied in the
Unified Approach to Furan Natural Products via Phosphine‐Palladium Catalysis
作者:Violet Yijang Chen、Ohyun Kwon
DOI:10.1002/anie.202015232
日期:2021.4.12
the construction of tetraalkyl furans remains non‐trivial. The prevalence of alkyl groups in bioactive furan natural products, combined with the desirable bioactivities of tetraalkyl furans, calls for a general synthetic protocol for polyalkyl furans. This paper describes a Michael–Heck approach, using sequential phosphine‐palladium catalysis, for the preparation of various polyalkyl furans from readily
An Iron-Catalyzed Bond-Making/Bond-Breaking Cascade Merges Cycloisomerization and Cross-Coupling Chemistry
作者:Pierre-Georges Echeverria、Alois Fürstner
DOI:10.1002/anie.201604531
日期:2016.9.5
reaction cascade that results in the net formation of two new C−C bonds while a C−Z bond in the substrate backbone is broken. Not only does this new manifold lend itself to the extrusion of heteroelements (Z=O, NR), but it can even be used for the cleavage of activatedC−C bonds. The reaction likely proceeds via metallacyclic intermediates, the iron center of which gains ate character before reductive elimination
A unique approach to biaryls was developed on the basis of propargyl vinyl ethers and dienophiles substrates via a gold(I)-initiated cycloisomerization/Diels–Alder/retro-Diels–Alder cascade reaction. The scope and mechanism of the reaction were investigated on the basis of a series of synthetic substrates, control experiments, and DFT calculations.