1598413-80-9Relevant academic research and scientific papers
An Electrochemically Promoted, Nickel-Catalyzed Mizoroki-Heck Reaction
Walker, Benjamin R.,Sevov, Christo S.
, p. 7197 - 7203 (2019)
Despite significant efforts to replace Pd-based catalysts with those of Ni, the Ni-catalyzed Mizoroki-Heck coupling of aryl halides and alkenes remains challenging. This work details the development of a Mizoroki-Heck reaction of aryl halides and a broad range of alkenes that utilizes electrochemistry as a means to promote Ni-catalyzed coupling under mild conditions. Stoichiometric studies implicate low-valent Ni complexes as key intermediates in route to rapid reactions with even unactivated alkenes. As such, electrochemistry is employed to readily provide the reducing potentials necessary to access these reactive intermediates and render the transformation catalytic. Cyclohexenone was found to be an unreactive substrate but a crucial additive that promotes facile electroreduction of the Ni catalyst and functionalization of other alkenes in high yields. Finally, preliminary mechanistic studies suggest that reactions proceed via an electron-chain transfer process that rapidly terminates but is reinitiated upon electroreduction.
Nickel-catalyzed Mizoroki-Heck reaction of aryl sulfonates and chlorides with electronically unbiased terminal olefins: High selectivity for branched products
Tasker, Sarah Z.,Gutierrez, Alicia C.,Jamison, Timothy F.
supporting information, p. 1858 - 1861 (2014/03/21)
Achieving high selectivity in the Heck reaction of electronically unbiased alkenes has been a longstanding challenge. Using a nickel-catalyzed cationic Heck reaction, we were able to achieve excellent selectivity for branched products (≥19:1 in all cases) over a wide range of aryl electrophiles and aliphatic olefins. A bidentate ligand with a suitable bite angle and steric profile was key to obtaining high branched/linear selectivity, whereas the appropriate base suppressed alkene isomerization of the product. Although aryl triflates are traditionally used to access the cationic Heck pathway, we have shown that, by using triethylsilyl trifluoromethanesulfonate, we can effect a counterion exchange of the catalytic nickel complex, such that cheaper and more stable aryl chlorides, mesylates, tosylates, and sulfamates can be used to yield the same branched products with high selectivity. Branching out: A Ni-catalyzed Heck reaction for the preparation of 1,1-disubstituted alkenes is presented. High selectivity for the branched products is achieved with electronically unbiased aliphatic terminal olefins. Regioselectivities remain consistently high (≥19:1) throughout. TESOTf=triethylsilyl trifluoromethanesulfonate. Copyright
