A metal- and catalyst-free photoinduced radical
cascade hydroalkylation of 1,7-enynes has been
disclosed. The process is triggered by a SET event involving a photoexcited
electron-donor-aceptor complex between NHPI ester and Hantzsch ester, which
decomposes to afford a tertiary radical that is readily trapped by the enyne. <a>The method provides an operationally simple, robust and
step-economical approach to the construction of diversely functionalized
dihydroquinolinones bearing quaternary-centers. A sequential one-pot hydroalkylation-isomerization
approach is also allowed giving access
to a family of quinolinones. A wide substrate scope and high functional group tolerance was observed in both approaches</a>.
The first iron-catalyzed three-component cross-coupling of unactivated olefins with alkyl halides and Grignard reagents is reported. The reaction operates under fast turnover frequency and tolerates a diverse range of sp2-hybridized nucleophiles, alkyl halides, and unactivated olefins bearing diverse functional groups to yield the desired 1,2-alkylarylated products with high regiocontrol. Further, we demonstrate that this protocol is amenable for the synthesis of new (hetero)carbocycles including tetrahydrofurans and pyrrolidines via a three-component radical cascade cyclization/arylation that forges three new C-C bonds.
Design and implementation of the first (asymmetric) Fe-catalyzed intra- and intermolecular difunctionalization of vinyl cyclopropanes (VCPs) with alkyl halides and aryl Grignard reagents has been realized via a mechanistically driven approach. Mechanistic studies support the diffusion of the alkyl radical intermediates out of the solvent cage to participate in an intra- or -intermolecular radical cascade with the VCP followed by re-entering the Fe radical cross-coupling cycle to undergo selective C(sp2)-C(sp3) bond formation. Overall, we provide new design principles for Fe-mediated radical processes and underscore the potential of using combined computations and experiments to accelerate the development of challenging transformations.
A radical cascade reaction of 2-aryloxy phenylacetylene with phosphine oxides promoted by K2S2O8 was developed, provided diphosphonyl xanthenes as products. This reaction proceeds under transition metal-free and mild conditions with...
A metal-free radical cascade methylation/cyclization of a wide range of N-alkyl-N-methacryloylbenzamides by using dicumyl peroxide as the methylating reagent provides a convenient access to a series of methylated isoquinoline-1,3-diones in moderate yields.
Rhodium(iii)-catalyzed enone carbonyl directed C–H activation/annulation of α-aroyl ketene dithioacetals with diazo compounds has been realized for the synthesis of β-quaternary indanones.
Stereoselective Synthesis of Tri- and Tetrasubstituted Olefins via 1,6-Additions of Diazo Compounds and Their Precursors to p-Quinone Methides
