Experimental and Theoretical Studies of the Reaction of the OH Radical with Alkyl Sulfides: 3. Kinetics and Mechanism of the OH Initiated Oxidation of Dimethyl, Dipropyl, and Dibutyl Sulfides: Reactivity Trends in the Alkyl Sulfides and Development of a Predictive Expression for the Reaction of OH with DMS

2009 ◽  
Vol 113 (24) ◽  
pp. 6697-6709 ◽  
Author(s):  
M. B. Williams ◽  
P. Campuzano-Jost ◽  
A. J. Hynes ◽  
A. J. Pounds
Keyword(s):  
Kinetics And Mechanism ◽  
Theoretical Studies ◽  
Oh Radical ◽  
Experimental And Theoretical Studies

The Stabilizing Effect of Pre-Equilibria: A Trifluoromethyl Complex as CF2 Reservoir in Catalytic Olefin Difluorocarbenation

2020 ◽  
Author(s):  
Thomas Louis-Goff ◽  
Huu Vinh Trinh ◽  
Eileen Chen ◽  
Arnold L. Rheingold ◽  
Christian Ehm ◽  
...  
Keyword(s):  
High Selectivity ◽  
Side Reactions ◽  
Theoretical Studies ◽  
Attractive Feature ◽  
Catalyst Recovery ◽  
Wide Range ◽  
Stabilizing Effect ◽  
Experimental And Theoretical Studies

A new, efficient, catalytic difluorocarbenation of olefins to give 1,1-difluorocyclopropanes is presented. The catalyst, an organobismuth complex, uses TMSCF<sub>3</sub> as a stoichiometric difluorocarbene source. We demonstrate both the viability and robustness of this reaction over a wide range of alkenes and alkynes, including electron-poor alkenes, to generate the corresponding 1,1-difluorocyclopropanes and 1,1-difluorocyclopropenes. Ease of catalyst recovery from the reaction mixture is another attractive feature of this method. In depth experimental and theoretical studies showed that the key difluorocarbene-generating step proceeds through a bismuth non-redox synchronous mechanism generating a highly reactive free CF<sub>2</sub> in an endergonic pre-equilibrium. It is the reversibility when generating the difluorocarbene that accounts for the high selectivity, while minimizing CF<sub>2</sub>-recombination side-reactions.

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