scholarly journals Design of Ru(II)-NHC-Diamine Precatalysts Directed by Ligand Cooperation: Applications and Mechanistic Investigations for Asymmetric Hydrogenation

2020 ◽  
Vol 142 (15) ◽  
pp. 7100-7107
Author(s):  
Wei Li ◽  
Tobias Wagener ◽  
Lars Hellmann ◽  
Constantin G. Daniliuc ◽  
Christian Mück-Lichtenfeld ◽  
...  
Keyword(s):  
Asymmetric Hydrogenation ◽  
Mechanistic Investigations

Three-Component [1+1+1] Cyclopropanation with Ruthenium(II)

2018 ◽  
Author(s):  
Tanner C. Jankins ◽  
Robert R. Fayzullin ◽  
Eugene Khaskin
Keyword(s):  
Quaternary Carbon ◽  
Poor Control ◽  
One Step ◽  
Synthetic Routes ◽  
Mechanistic Investigations ◽  
Chiral Centers ◽  
Metal Catalyzed ◽  
The Right ◽  
Substituted Cyclopropanes

We report a one-step, Ru(II)-catalyzed cyclopropanation reaction that is conceptually different from the previously reported protocols that include Corey-Chaykovsky, Simmons-Smith, and metal catalyzed carbene attack on olefins. Under the current protocol, various alcohols are transformed into sulfone substituted cyclopropanes with excellent isolated yields and diastereoselectivities. This new reaction forms highly congested cyclopropane products with three new C–C bonds, three or two new chiral centers and one new quaternary carbon center. 22 examples of isolated substrates are given. Previously reported synthetic routes for similar substrates are all multi-step, linear routes that proceed with overall low yields and poor control of stereochemistry. Experimental mechanistic investigations suggest initial metal-catalyzed dehydrogenation of the alcohol substrate and catalyst independent stepwise attack of two equivalents of sulfone on the aldehyde under basic conditions. While the Ru(II) is only responsible for the initial dehydrogenation step, the rate of aldehyde formation is crucial to maintaining the right balance of intermediates needed to afford the cyclopropane product.

Visible Light-Induced Sulfonylation/Arylation of Styrenes in a Double Radical Three-Component Photoredox Reaction

2019 ◽  
Author(s):  
Benjamin Lipp ◽  
Lisa Marie Kammer ◽  
Murat Kucukdisli ◽  
Adriana Luque ◽  
Jonas Kühlborn ◽  
...  
Keyword(s):  
Visible Light ◽  
Radical Formation ◽  
Three Component Reaction ◽  
Broad Variety ◽  
Styrene Derivatives ◽  
Mechanistic Investigations

Simultaneous sulfonylation/arylation of styrene derivatives is achieved in a photoredox-catalyzed three-component reaction using visible light. A broad variety of difunctionalized products is accessible in mostly excellent yields and high diastereoselectivity. The developed reaction is scalable and suitable for the modification of styrene-functionalized biomolecules. Mechanistic investigations suggest the transformation to be operating through a designed sequence of radical formation and radical combination.<br>

Asymmetric Hydrogenation of Benzalacetone Catalyzed by RuCl2 (TPPTS) 2-(S,S)-DPENDS in Water Medium

2010 ◽  
Vol 31 (3) ◽  
pp. 273-277
Author(s):  
Jinbo WANG ◽  
Ruixiang QIN ◽  
Wei XIONG ◽  
Yun JIA ◽  
Derong LIU ◽  
...  
Keyword(s):  
Asymmetric Hydrogenation ◽  
Water Medium
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