scholarly journals Asymmetric Synthesis of Spiropyrazolones by Sequential Organo- and Silver Catalysis

2015 ◽  
Vol 128 (5) ◽  
pp. 1829-1832 ◽  
Author(s):  
Daniel Hack ◽  
Alexander B. Dürr ◽  
Kristina Deckers ◽  
Pankaj Chauhan ◽  
Nico Seling ◽  
...  
2015 ◽  
Vol 55 (5) ◽  
pp. 1797-1800 ◽  
Author(s):  
Daniel Hack ◽  
Alexander B. Dürr ◽  
Kristina Deckers ◽  
Pankaj Chauhan ◽  
Nico Seling ◽  
...  

ChemInform ◽  
2016 ◽  
Vol 47 (22) ◽  
Author(s):  
Daniel Hack ◽  
Alexander B. Duerr ◽  
Kristina Deckers ◽  
Pankaj Chauhan ◽  
Nico Seling ◽  
...  

Synthesis ◽  
2016 ◽  
Vol 48 (19) ◽  
pp. 3207-3216 ◽  
Author(s):  
Uğur Kaya ◽  
Pankaj Chauhan ◽  
Kristina Deckers ◽  
Rakesh Puttreddy ◽  
Kari Rissanen ◽  
...  

A low catalyst loading of a squaramide (0.5 mol%) and a silver(I) salt (1 mol%) efficiently catalyzes a one-pot asymmetric Michael addition/hydroalkoxylation reaction between 1,3-diketones and alkyne-tethered nitroalkenes. Depending on the 1,3-dicarbonyl substrate this cooperative catalytic approach opens access to tetrahydrobenzofurans or annulated dihydropyrans in moderate to excellent yields and very good to excellent enantioselectivities.


2018 ◽  
Author(s):  
Marc Montesinos-Magraner ◽  
Matteo Costantini ◽  
Rodrigo Ramirez-Contreras ◽  
Michael E. Muratore ◽  
Magnus J. Johansson ◽  
...  

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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