An efficient [3+2] annulation for the asymmetric synthesis of densely-functionalized pyrrolidinones and γ-butenolides

2020 ◽  
Vol 56 (76) ◽  
pp. 11295-11298
Author(s):  
Hui Qian ◽  
Song Sun ◽  
Wanxiang Zhao ◽  
Jianwei Sun
Keyword(s):  
Asymmetric Synthesis ◽  
Direct Synthesis ◽  
Siloxy Alkynes

Disclosed here is a new [3+2] annulation of siloxy alkynes that provides robust access to highly enantioenriched, densely-substituted pyrrolidinones and γ-butenolides, whose direct synthesis remains challenging.

scholarly journals Direct synthesis of anomeric tetrazolyl iminosugars from sugar-derived lactams

2021 ◽  
Vol 17 ◽  
pp. 115-123
Author(s):  
Michał Mateusz Więcław ◽  
Bartłomiej Furman
Keyword(s):  
Asymmetric Synthesis ◽  
Multicomponent Reaction ◽  
Direct Synthesis ◽  
X Ray

Herein we present the direct asymmetric synthesis of tetrazole-functionalized 1-deoxynojirimycin derivatives from simple sugars via a Schwartz’s reagent-mediated reductive amide functionalization followed by a variant of the Ugi–azide multicomponent reaction. The anomeric configurations of two products were unambiguously confirmed by X-ray analysis. This work also describes examples of interesting further transformations of the title products. Finally, some surprising observations regarding the mechanism of their formation were made.

scholarly journals Direct synthesis of anomeric tetrazolyl iminosugars from sugar-derived lactams

2020 ◽  
Author(s):  
Michał Mateusz Więcław ◽  
Bartłomiej Furman
Keyword(s):  
Asymmetric Synthesis ◽  
Direct Synthesis ◽  
X Ray

Herein we present the direct asymmetric synthesis of tetrazole-functionalized 1-deoxynojirimycin derivatives from simple sugars via a Schwartz’s reagent-mediated reductive amide functionalization followed by a variant of the Ugi-azide multi-component reaction. The anomeric configurations of two products were unambiguously confirmed by X-ray analysis. This work also describes examples of interesting further transformations of the title products. Finally, some surprising observations regarding the mechanism of their formation were made.

General Cyclopropane Assembly via Enantioselective Redox-Active Carbene Transfer to Aliphatic Olefins

2018 ◽  
Author(s):  
Marc Montesinos-Magraner ◽  
Matteo Costantini ◽  
Rodrigo Ramirez-Contreras ◽  
Michael E. Muratore ◽  
Magnus J. Johansson ◽  
...  
Keyword(s):  
Total Synthesis ◽  
Asymmetric Synthesis ◽  
Chemical Space ◽  
Synthetic Approach ◽  
Asymmetric Cyclopropanation ◽  
Redox Active ◽  
Wide Range ◽  
Leaving Group ◽  
Stereoelectronic Properties ◽  
Carbene Transfer

Asymmetric cyclopropane synthesis currently requires bespoke strategies, methods, substrates and reagents, even when targeting similar compounds. This limits the speed and chemical space available for discovery campaigns. Here we introduce a practical and versatile diazocompound, and we demonstrate its performance in the first unified asymmetric synthesis of functionalized cyclopropanes. We found that the redox-active leaving group in this reagent enhances the reactivity and selectivity of geminal carbene transfer. This effect enabled the asymmetric cyclopropanation of a wide range of olefins including unactivated aliphatic alkenes, enabling the 3-step total synthesis of (–)-dictyopterene A. This unified synthetic approach delivers high enantioselectivities that are independent of the stereoelectronic properties of the functional groups transferred. Our results demonstrate that orthogonally-differentiated diazocompounds are viable and advantageous equivalents of single-carbon chirons<i>.</i>

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