Enantioselective Intermolecular Mannich-Type Interception of Phenolic Oxonium Ylide for the Direct Assembly of Chiral 2,2-Disubstituted Dihydrobenzofurans

ACS Catalysis ◽  
2021 ◽  
pp. 6750-6756
Author(s):  
Kemiao Hong ◽  
Shanliang Dong ◽  
Xinxin Xu ◽  
Zhijing Zhang ◽  
Taoda Shi ◽  
...  
Keyword(s):  
Direct Assembly ◽  
Oxonium Ylide

Macrocycles of Higher Ortho-Phenylenes: Assembly and Folding

2019 ◽  
Author(s):  
Zacharias Kinney ◽  
Viraj Kirinda ◽  
Scott Hartley
Keyword(s):  
Chemical Shift ◽  
Higher Order ◽  
Order Structure ◽  
Complex Geometries ◽  
Spatial Relationships ◽  
Predominant Species ◽  
Bite Angle ◽  
Direct Assembly

<p>Higher-order structure in abiotic foldamer systems represents an important but largely unrealized goal. As one approach to this challenge, covalent assembly can be used to assemble macrocycles with foldamer subunits in well-defined spatial relationships. Such systems have previously been shown to exhibit self-sorting, new folding motifs, and dynamic stereoisomerism, yet there remain important questions about the interplay between folding and macrocyclization and the effect of structural confinement on folding behavior. Here, we explore the dynamic covalent assembly of extended <i>ortho</i>-phenylenes (hexamer and decamer) with rod-shaped linkers. Characteristic <sup>1</sup>H chemical shift differences between cyclic and acyclic systems can be compared with computational conformer libraries to determine the folding states of the macrocycles. We show that the bite angle provides a measure of the fit of an <i>o</i>-phenylene conformer within a shape-persistent macrocycle, affecting both assembly and ultimate folding behavior. For the <i>o</i>-phenylene hexamer, the bite angle and conformer stability work synergistically to direct assembly toward triangular [3+3] macrocycles of well-folded oligomers. For the decamer, the energetic accessibility of conformers with small bite angles allows [2+2] macrocycles to be formed as the predominant species. In these systems, the <i>o</i>-phenylenes are forced into unusual folding states, preferentially adopting a backbone geometry with distinct helical blocks of opposite handedness. The results show that simple geometric restrictions can be used to direct foldamers toward increasingly complex geometries.</p>

Macrocycles of Higher ortho-Phenylenes: Assembly and Folding

2019 ◽  
Author(s):  
Zacharias Kinney ◽  
Viraj Kirinda ◽  
Scott Hartley
Keyword(s):  
Chemical Shift ◽  
Higher Order ◽  
Order Structure ◽  
Complex Geometries ◽  
Spatial Relationships ◽  
Predominant Species ◽  
Bite Angle ◽  
Direct Assembly

<p>Higher-order structure in abiotic foldamer systems represents an important but largely unrealized goal. As one approach to this challenge, covalent assembly can be used to assemble macrocycles with foldamer subunits in well-defined spatial relationships. Such systems have previously been shown to exhibit self-sorting, new folding motifs, and dynamic stereoisomerism, yet there remain important questions about the interplay between folding and macrocyclization and the effect of structural confinement on folding behavior. Here, we explore the dynamic covalent assembly of extended <i>ortho</i>-phenylenes (hexamer and decamer) with rod-shaped linkers. Characteristic <sup>1</sup>H chemical shift differences between cyclic and acyclic systems can be compared with computational conformer libraries to determine the folding states of the macrocycles. We show that the bite angle provides a measure of the fit of an <i>o</i>-phenylene conformer within a shape-persistent macrocycle, affecting both assembly and ultimate folding behavior. For the <i>o</i>-phenylene hexamer, the bite angle and conformer stability work synergistically to direct assembly toward triangular [3+3] macrocycles of well-folded oligomers. For the decamer, the energetic accessibility of conformers with small bite angles allows [2+2] macrocycles to be formed as the predominant species. In these systems, the <i>o</i>-phenylenes are forced into unusual folding states, preferentially adopting a backbone geometry with distinct helical blocks of opposite handedness. The results show that simple geometric restrictions can be used to direct foldamers toward increasingly complex geometries.</p>

scholarly journals Dirhodium Carboxylate Catalysts from 2‐Fenchyloxy or 2‐Menthyloxy Arylacetic Acids: Enantioselective C−H Insertion, Aromatic Addition and Oxonium Ylide Formation/Rearrangement

ChemCatChem ◽  
2021 ◽  
Author(s):  
Aoife M. Buckley ◽  
Daniel C. Crowley ◽  
Thomas A. Brouder ◽  
Alan Ford ◽  
U. B. Rao Khandavilli ◽  
...  
Keyword(s):  
Arylacetic Acids ◽  
Oxonium Ylide

Variations in Complementary Hydrogen Bonds Direct Assembly Patterns of Isosteric Polyheteroaromatics at Surfaces

2021 ◽  
Author(s):  
David L. Wisman ◽  
Heechan Kim ◽  
Chungryeol Kim ◽  
Tobias W. Morris ◽  
Dongwhan Lee ◽  
...  
Keyword(s):  
Hydrogen Bonds ◽  
Direct Assembly

Direct assembly of a metallodendrimer encompassing seven triruthenium clusters units

2012 ◽  
Vol 390 ◽  
pp. 148-153 ◽  
Author(s):  
Sergio H. Toma ◽  
Jonnatan J. Santos ◽  
Sofia Nikolaou ◽  
Koiti Araki ◽  
Henrique E. Toma
Keyword(s):  
Direct Assembly

scholarly journals Control of Chemoselectivity in Dirhodium(II)-Catalyzed Reaction of 5,6-Dioxygenated 2-Diazo-3-oxohexanoates: C-H Insertion Reaction versus Oxonium Ylide Formation.

1998 ◽  
Vol 46 (7) ◽  
pp. 1182-1183 ◽  
Author(s):  
Takayuki YAKURA ◽  
Akiharu UEKI ◽  
Yukiko MORIOKA ◽  
Toyoshige KURATA ◽  
Kenji TANAKA ◽  
...  
Keyword(s):  
Insertion Reaction ◽  
Oxonium Ylide

Dinuclear zinc-catalyzed asymmetric [3+2] cyclization reaction for direct assembly of chiral α-amino-γ-butyrolactones bearing three stereocenters

2021 ◽  
Author(s):  
Wen-Peng Yang ◽  
Shi-Kun Jia ◽  
Tian-Tian Liu ◽  
Yuan-Zhao Hua ◽  
Mincan Wang
Keyword(s):  
Lewis Acid ◽  
Cyclization Reaction ◽  
Activation Model ◽  
Direct Assembly ◽  
Brønsted Base ◽  
Cooperative Activation

An efficient enantioselective [3+2] cyclization reaction of α-hydroxy-1-indanones and alkylidene azlactones has been developed with chiral dinuclear zinc catalysts via a Brønsted base and Lewis acid cooperative activation model. This...

Direct Assembly of Polysubstituted Furans via C(sp 3 )−H Bond Functionalization by Using Dimethyl Sulfoxide as a Dual Synthon

2019 ◽  
Vol 361 (5) ◽  
pp. 1084-1091 ◽  
Author(s):  
Yufeng Liu ◽  
Yuqun Hu ◽  
Zhongzhong Cao ◽  
Xi Zhan ◽  
Weiping Luo ◽  
...  
Keyword(s):  
Dimethyl Sulfoxide ◽  
Bond Functionalization ◽  
Direct Assembly
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