A nickel-catalyzed,
enantioselective, three-component fluoroalkylarylation
of unactivated alkenes with aryl halides and perfluoroalkyl iodides
has been described. This cross-electrophile coupling protocol utilizes
a chiral nickel/BiOx system as well as a pendant chelating group to
facilitate the challenging three-component, asymmetric difunctionalization
of unactivated alkenes, providing direct access to valuable chiral
β-fluoroalkyl arylalkanes with high efficiency and excellent
enantioselectivity. The mild conditions allow for a broad substrate
scope as well as good functional group toleration.
The development of catalytic carboacylation of simple olefins, which would enable the rapid construction of ketones with high levels of complexity and diversity, is very challenging. To date, the vast majority of alkene carboacylation reactions are typically restricted to single- and two-component methodologies. Here we describe a three-component carboacylation of alkenes via the merger of radical chemistry with nickel catalysis. This reaction manifold utilizes a radical relay strategy involving radical addition to an alkene followed by alkyl radical capture by an acyl-nickel complex to forge two vicinal C−C bonds under mild conditions. Excellent chemoselectivity and regioselectivity have been achieved by utilizing a pendant weakly chelating group. This versatile protocol allows for facile access to a wide range of important β-fluoroalkyl ketones from simple starting materials.
A regioselective, intermolecular 1,2-alkylarylation of alkenes with aryl halides and alkyl oxalates has been developed via photoredox/nickel dual catalysis. This dual-catalytic protocol involves a radical relay process, where radical addition is followed by a nickelassisted coupling, forging two consecutive C−C bonds in a single operation. The mild and redox-neutral conditions allow for good compatibility in the scope of olefins, (hetero)aryl halides, as well as alkyl oxalates.Letter pubs.acs.org/OrgLett
A copper and iodine-mediated C-H oxidative sulfenylation of olefins with diaryl disulfides has been developed for the stereospecific synthesis of vinyl thioether. With the combination of Cu(OTf)2 and I2, a variety of terminal alkenes underwent oxidative coupling reaction with various diaryl disulfides successfully to afford the corresponding E-vinyl sulfides in moderate to good yields.
A new transition-metal-free transformation of trifluoropropanamides into cyanoformamides through a sequence of C-CF bond cleavage and nitrogenation using tert-butyl nitrite as the nitrogen source is described. The method features direct detrifluoromethylation, broad substrate scopes, and excellent selectivity control, representing a new shortcut for constructing the nitrile group involving C-CF σ-bond cleavage.
An iron-promoted tandem carboxamidation and cyclization between aryl isonitriles and formamides has been developed. The one-pot strategy can be applied to a wide range of 2-isocyanobiphenyls and formamides with excellent functional group tolerance for the synthesis of phenanthridine-6-carboxamides in moderate to excellent yields.
Catalytic, intermolecular difunctionalization of alkenes represents an efficient and diverse protocol for the buildup of molecular complexity from abundant materials by forging two chemical bonds in a single operation. Despite important progress in this area, transition-metal-catalyzed three-component difunctionalization of unactivated alkenes remains underdeveloped, mainly because of the low reactivity, reduced polarization, and high tendency toward β-hydride elimination of these compounds. In this context, nickel-catalyzed, selective, intermolecular difunctionalization methods that generally proceed via two distinct reaction pathways, migratory insertion of nickel species into alkenes and radical addition to alkenes, have been developed. This short review highlights recent advances in this area.1 Introduction2 Nickel-Catalyzed Three-Component Difunctionalization of Unactivated Alkenes via Migratory Insertion Processes3 Nickel-Catalyzed Three-Component Difunctionalization of Unactivated Alkenes via Radical Processes4 Conclusions and Perspectives
A four-component radical cascade trifluoromethylation of alkenes, enabled by an electron-donor–acceptor complex between Togni's reagent and Hantzsch ester, has been described.
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