Catalyst- and Substituent-Controlled Switching of Chemoselectivity for the Enantioselective Synthesis of Fully Substituted Cyclobutane Derivatives via 2 + 2 Annulation of Vinylogous Ketone Enolates and Nitroalkene

2018 ◽  
Vol 20 (24) ◽  
pp. 7835-7839 ◽  
Author(s):  
Pavan Sudheer Akula ◽  
Bor-Cherng Hong ◽  
Gene-Hsiang Lee
Keyword(s):  
Enantioselective Synthesis ◽  
Controlled Switching ◽  
Ketone Enolates ◽  
Cyclobutane Derivatives

Enantioselective Functionalization of Prochiral Cyclobutanones and Cyclobutenones

Synlett ◽  
2021 ◽  
Author(s):  
Memg Wang ◽  
Changxu Zhong ◽  
Ping Lu
Keyword(s):  
Asymmetric Synthesis ◽  
Membered Ring ◽  
Enantioselective Synthesis ◽  
Ring Compounds ◽  
Recent Advances ◽  
Cyclobutane Derivatives

Enantioselective synthesis of cyclobutane derivatives is still a challenging topic in asymmetric synthesis. [2+2]-Cycloaddition and skeleton rearrangement are two primary strategies to this end. Recently, functionalization of cyclobutanones and cyclobutenones, which are readily available via [2+2]-cycloadditions as prochiral substrates, has emerged as a powerful tool to access versatile four-membered ring compounds. Herein, we summarize some recent advances in these areas from our and other groups.

scholarly journals Ir-Catalyzed Chemodivergent Allenylic Alkylation of Vinyl Az-ides: Highly Enantioselective Synthesis of α-Allenylic Amides and Ketones

2021 ◽  
Author(s):  
Aditya Chakrabarty ◽  
Santanu Mukherjee
Keyword(s):  
Absolute Configuration ◽  
Molecular Sieves ◽  
Alkylating Agent ◽  
Enantioselective Synthesis ◽  
Reaction Conditions ◽  
Ketone Enolates ◽  
Coupling Strategy ◽  
Vinyl Azides ◽  
Alkylation Reactions ◽  
Asymmetric Transformation

Enantioselective allenylic alkylation reactions of unstabilized enolates have never been reported. We now present a unified fragment-coupling strategy for the first enantioselective synthesis of α-allenylic amides and ketones through allenyl-ic alkylation of vinyl azides. In these chemodivergent reactions, cooperatively catalyzed by Ir(I)/(phosphoramidite,olefin) complex and Sc(OTf)3, vinyl azides act as the surrogate for both amide enolates and ketone enolates. The desiccant (molecular sieves) plays a crucial role in controlling the chemodivergency of this enantioconvergent and regioselective reaction: Under otherwise identical reaction conditions, the presence of the desiccant led to α-allenylic amides while its absence resulted in α-allenylic ketones from the same substrate combinations. Utilizing race-mic allenylic alcohols as the alkylating agent, the overall process represents a dynamic kinetic asymmetric transformation (DyKAT), where both α-allenylic amides and ketones are formed with the same absolute configuration generally with outstanding enantioselectivity. To the best of our knowledge, this is the first example of the use of vinyl azide as the ketone enolate surrogate in an enantioselective transformation.

Catalytic cascade aldol–cyclization of tertiary ketone enolates for enantioselective synthesis of keto-esters with a C–F quaternary stereogenic center

2016 ◽  
Vol 14 (30) ◽  
pp. 7295-7303 ◽  
Author(s):  
Wanxing Sha ◽  
Lijun Zhang ◽  
Wenzhong Zhang ◽  
Haibo Mei ◽  
Vadim A. Soloshonok ◽  
...  
Keyword(s):  
Cascade Reaction ◽  
Enantioselective Synthesis ◽  
Keto Esters ◽  
Aldol Cyclization ◽  
Ketone Enolates ◽  
Stereogenic Center

The first enantioselective catalytic aldol–cyclization cascade reaction of detrifluoroacetylatively in situ generated tertiary enolates with methyl 2-formylbenzoate is reported.

Catalytic enantioselective synthesis of indolizino[8,7-b]indole alkaloid derivatives based on the tandem reaction of tertiary enamides

2021 ◽  
Author(s):  
Xin-Ming Xu ◽  
Ming Xie ◽  
Jiazhu Li ◽  
Mei-Xiang Wang
Keyword(s):  
Indole Alkaloid ◽  
Enantioselective Synthesis ◽  
High Yield ◽  
Tandem Reaction ◽  
Indole Derivatives

An exquisite Pybox/Cu(OTf)2-catalyzed asymmetric tandem reaction of tertiary enamides was developed, which enabled the expeditious synthesis of indolizino[8,7-b]indole derivatives in high yield, excellent enantioselectivity and diastereoselectivity.

Enantioselective Synthesis of Azamerone

2018 ◽  
Author(s):  
Matthew L. Landry ◽  
Grace McKenna ◽  
Noah Burns
Keyword(s):  
Late Stage ◽  
Cross Coupling ◽  
Enantioselective Synthesis ◽  
Selective Synthesis

A concise and selective synthesis of the dichlorinated meroterpenoid azamerone is described. The paucity of tactics for the synthesis of chiral organochlorides motivated the development of unique strategies for accessing these motifs in enantioenriched forms. The route features a novel enantioselective chloroetherification reaction, a Pd-catalyzed cross-coupling between a quinone diazide and a boronic hemiester, and a late-stage tetrazine [4+2]-cycloaddition/oxidation cascade.

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