Gold-catalyzed domino cyclization enabling construction of diverse fused azaspiro tetracyclic scaffolds: a cascade catalysis mechanism due to a substrate and counterion

2020 ◽  
Vol 10 (8) ◽  
pp. 2415-2426 ◽  
Author(s):  
Yunhe Li ◽  
Xiang Zhao
Keyword(s):  
Detailed Mechanism ◽  
Catalysis Mechanism ◽  
Dual Catalysis ◽  
Cascade Catalysis

The detailed mechanism and origins of gold-catalyzed domino cyclization to diverse fused azaspiro tetracyclic scaffolds by cooperative dual catalysis and cascade catalysis are systematically studied.

2.1.1 General Principles of Metal/Organocatalyst Dual Catalysis

2020 ◽  
Author(s):  
Z. Shao ◽  
Y.-H. Deng
Keyword(s):  
Catalytic System ◽  
Reaction Mechanisms ◽  
Bifunctional Catalysis ◽  
Metal Catalysis ◽  
Cooperative Catalysis ◽  
Unique Reaction ◽  
Dual Catalysis ◽  
Double Activation ◽  
Multiple Relay ◽  
Cascade Catalysis

AbstractMetal/organocatalyst dual catalysis is a privileged catalytic strategy which involves both a metal-based catalyst and an organocatalyst to catalyze the organic transformation. Based on the type of activation of substrates with both catalysts, there are seven kinds of dual catalysis; namely cooperative catalysis, cascade catalysis, sequential catalysis, double activation catalysis, restorative catalysis, bifunctional catalysis, and multiple relay catalysis. The generic activation of the metal-based catalyst and the organocatalyst applied in the dual-catalytic system is summarized. In these dual-catalytic approaches, the advantages of both metal catalysis and organocatalysis are converged to achieve many transformations that were previously inaccessible or challenging by any single-catalyst paradigm, to develop new reactions, to discover unique reaction mechanisms, and even to allow for stereodivergent synthesis.

Gold-catalyzed domino cyclization to diverse polyheterocyclic frameworks: mechanism, origin of the cooperative hydrogen bond, and role of π-stacking interactions

2020 ◽  
Vol 10 (12) ◽  
pp. 4109-4118 ◽  
Author(s):  
Yunhe Li ◽  
Xiang Zhao
Keyword(s):  
Hydrogen Bond ◽  
Stacking Interactions ◽  
Detailed Mechanism ◽  
Cooperative Catalysis ◽  
Π Stacking ◽  
Cascade Catalysis

The detailed mechanism and origins of gold-catalyzed domino cyclization to diverse fused polyheterocyclic frameworks by cooperative catalysis and cascade catalysis were studied systematically.

Microwave-assisted heteropolyanion-based ionic liquid promoted sustainable protocol to N-heteroaryl amides via N-directing dual catalyzed oxidative amidation of aldehydes

RSC Advances ◽  
2016 ◽  
Vol 6 (109) ◽  
pp. 107699-107707 ◽  
Author(s):  
Renzhong Fu ◽  
Yang Yang ◽  
Weihua Jin ◽  
Hui Gu ◽  
Xiaojun Zeng ◽  
...  
Keyword(s):  
Ionic Liquid ◽  
Ionic Liquids ◽  
Microwave Assisted ◽  
Catalysis Mechanism ◽  
Dual Catalysis ◽  
Oxidative Amidation

A procedure for the synthesis of N-heteroaryl amides directly from oxidative amidation of aldehydes catalyzed by heteropolyanion-based ionic liquids has been reported. The proposed N-directing dual-catalysis mechanism was briefly investigated.

Bismuth Oxyiodide Couples with Glucose Oxidase: A Special Synergized Dual-Catalysis Mechanism for Photoelectrochemical Enzymatic Bioanalysis

2018 ◽  
Vol 10 (4) ◽  
pp. 3372-3379 ◽  
Author(s):  
Ling Zhang ◽  
Yi-Fan Ruan ◽  
Yan-Yu Liang ◽  
Wei-Wei Zhao ◽  
Xiao-Dong Yu ◽  
...  
Keyword(s):  
Glucose Oxidase ◽  
Catalysis Mechanism ◽  
Dual Catalysis

Anisotropy of interfacial defects in the initial stage of MOVPE GaAs growth On Si

1990 ◽  
Vol 48 (4) ◽  
pp. 592-593
Author(s):  
C. Vannuffel ◽  
C. Schiller ◽  
J. P. Chevalier
Keyword(s):  
Early Stage ◽  
Threading Dislocations ◽  
Mbe Growth ◽  
Detailed Mechanism ◽  
Si Substrates ◽  
Initial Stage ◽  
Interfacial Defects ◽  
Interfacial Dislocations ◽  
Step Growth ◽  
Essential Problem

Recently, interest has focused on the epitaxy of GaAs on Si as a promising material for electronic applications, potentially for integration of optoelectronic devices on silicon wafers. The essential problem concerns the 4% misfit between the two materials, and this must be accommodated by a network of interfacial dislocations with the lowest number of threading dislocations. It is thus important to understand the detailed mechanism of the formation of this network, in order to eventually reduce the dislocation density at the top of the layers.MOVPE growth is carried out on slightly misoriented, (3.5°) from (001) towards , Si substrates. Here we report on the effect of this misorientation on the interfacial defects, at a very early stage of growth. Only the first stage, of the well-known two step growth process, is thus considered. Previously, we showed that full substrate coverage occured for GaAs thicknesses of 5 nm in contrast to MBE growth, where substantially greater thicknesses are required.

Concise Synthesis of GB22 by Endo-Selective Siloxycyclopropane Arylation

2019 ◽  
Author(s):  
Hannah E. Burdge ◽  
Takuya Oguma ◽  
Takahiro Kawajiri ◽  
Ryan Shenvi
Keyword(s):  
Intramolecular Cyclization ◽  
Cross Coupling ◽  
Building Blocks ◽  
Ring Expansion ◽  
Dual Catalysis ◽  
Acid Labile

<div><div><div><p>The first synthesis of GB22 was accomplished by a con- cise, modular route. Two building blocks converged in a novel sp3-sp2 attached-ring coupling that used Ir/Ni dual-catalysis to reverse the regioselectivity of siloxycy- clopropane arylation. This cross-coupling proved general to access β-substituted tetralones via ring-expansion of indanone-derived siloxycyclopropanes. The congested, bridging rings of the GB alkaloids were completed using an aluminum-HFIP complex that effected intramolecular cyclization of an acid-labile substrate.</p></div></div></div>

Concise Synthesis of GB22 by Endo-Selective Siloxycyclopropane Arylation

2019 ◽  
Author(s):  
Hannah E. Burdge ◽  
Takuya Oguma ◽  
Takahiro Kawajiri ◽  
Ryan Shenvi
Keyword(s):  
Intramolecular Cyclization ◽  
Cross Coupling ◽  
Building Blocks ◽  
Ring Expansion ◽  
Dual Catalysis ◽  
Acid Labile

<div><div><div><p>The first synthesis of GB22 was accomplished by a con- cise, modular route. Two building blocks converged in a novel sp3-sp2 attached-ring coupling that used Ir/Ni dual-catalysis to reverse the regioselectivity of siloxycy- clopropane arylation. This cross-coupling proved general to access β-substituted tetralones via ring-expansion of indanone-derived siloxycyclopropanes. The congested, bridging rings of the GB alkaloids were completed using an aluminum-HFIP complex that effected intramolecular cyclization of an acid-labile substrate.</p></div></div></div>

Cascade CuH-Catalyzed Conversion of Alkynes to Enantioenriched 1,1-Disubstituted Products

2019 ◽  
Author(s):  
De-Wei Gao ◽  
Yang Gao ◽  
Huiling Shao ◽  
Tian-Zhang Qiao ◽  
Xin Wang ◽  
...  
Keyword(s):  
Organic Synthesis ◽  
Medicinal Chemistry ◽  
Proteasome Inhibitors ◽  
Building Blocks ◽  
Unique Role ◽  
Efficient Strategy ◽  
Carbon Centers ◽  
Rapid Access ◽  
Cascade Catalysis ◽  
Privileged Scaffolds

Enantioenriched <i>α</i>-aminoboronic acids play a unique role in medicinal chemistry and have emerged as privileged pharmacophores in proteasome inhibitors. Additionally, they represent synthetically useful chiral building blocks in organic synthesis. Recently, CuH-catalyzed asymmetric alkene hydrofunctionalization has become a powerful tool to construct stereogenic carbon centers. In contrast, applying CuH cascade catalysis to achieve reductive 1,1-difunctionalization of alkynes remains an important, but largely unaddressed, synthetic challenge. Herein, we report an efficient strategy to synthesize <i>α</i>-aminoboronates <i>via </i>CuH-catalyzed hydroboration/hydroamination cascade of readily available alkynes. Notably, this transformation selectively delivers the desired 1,1-heterodifunctionalized product in favor of alternative homodifunctionalized, 1,2-heterodifunctionalized, or reductively monofunctionalized byproducts, thereby offering rapid access to these privileged scaffolds with high chemo-, regio- and enantioselectivity.<br>

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