A free-radical cascade methylation/cyclization of a wide range of N-arylacrylamides and isocyanides is demonstrated by using dicumyl peroxide as the methylating reagent, which provides a convenient and selective access to various methylated N-heterocycles such as oxindoles and phenanthridines.
A free-radical-promoted aryl/heteroaryl C-H silylation using hydrosilane was developed. This cross-dehydrogenative silylation enables both electron-rich and electron-poor aromatics to afford the desired arylsilanes in unique selectivity. A "para-selectivity" was observed by examination of over 54 examples. This exceptional orientation is quite different from that in Friedel-Crafts C-H silylation or transition-metal-catalyzed dehydrogenative silylation.
A C-C formation of an electron-rich N-heterocycle with fluorinated alcohol is developed. Through this radical-triggered cross-dehydrogenative coupling strategy, a wide range of useful building blocks such as C3 hydroxyfluoroalkylated indoles and pyrroles can be site-specifically synthesized. Mechanistic studies indicate a single-electron-transfer initiated radical cycle would be involved.
A free-radical mediated highly ordered radical addition/cyclization/(sp(3))C-C(sp(3)) formation domino reaction is developed. Three new C-C bonds are formed one by one in a mixed system. Furthermore, it represents the first example of cascade C-C bond formation via selective functionalization of α-hydroxyl-C(sp(3))-H in fluorinated alcohols.
A Free-Radical Cascade Methylation/Cyclization of N-Arylacrylamides and Isocyanides with Dicumyl Peroxide. -Dicumyl peroxide is an efficient methyl radical donor for the methylation/cyclization reaction of N-arylacrylamides and isocyanides providing oxindoles and phenanthridines in reasonable yields. -(XU, Z.; YAN, C.; LIU*, Z.-Q.; Org. Lett. 16 (2014) 21, 5670-5673, http://dx.
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