RESUMEN
A mild and catalyst-free sunlight induced protocol for the remote meta bromination of electron-deficient indoles is described for the first time. Herein, N-bromosaccharin is activated by sunlight irradiation. Alternately, a synergistic activation model (Sc(OTf)3 /HFIP) has also been developed for the activation of haloniums, complementary to the light induced strategy. In addition, the cascade C6-H bromination and benzylic C-H oxidation under photocatalytic conditions was also discussed. High regio-and chem-selectivity, mild reaction conditions, and scalability demonstrate great potential of the developed methods in practical applications and further functionalization.
RESUMEN
An efficient and convenient iridium(iii) catalyzed ortho-C-H bond amidation of weakly coordinating benzamides treated with readily available sulfonyl azides as the amino source has been described. In this transformation, ionic liquids represents an ideal reaction medium, giving rise to a broad range of amidation products under mild conditions in the open air. This protocol offers moderate to excellent chemical yields, exclusive regioselectivities, and good functional group tolerance.
RESUMEN
We developed a general and sustainable approach for the regioselective deoxygenative chalcogenation of 7-azindole N-oxides; the combination of an internal oxidant and a green solvent has been used successfully for the synthesis of mono- and dichalcogenyl 7-azaindoles which are of pharmaceutical interest. The regioselectivity is tunable by the variation of the reaction conditions. I2/PEG was established as an efficient and reusable catalytic system for C-H chalcogenation. This developed methodology has great potential for practical utility, with a broad substrate scope, green reaction conditions, and operational simplicity.
RESUMEN
A phosphinic amide is introduced as a directing group for the ortho C-H alkenylation of anilines. The new donor group distinguishes itself from existing ones by assisting the C-H bond activation of anilides without (NH group) and with alkylation (NMe group) at the amide nitrogen atom. The reactivity is even reversed with the methyl-substituted anilide being more reactive than its unsubstituted counterpart. Electron-donating substituents at the arene ring enhance their reactivity while halogenation is not tolerated. The phosphinic amide also enables the C-7-selective C-H alkenylation of indoline.
RESUMEN
An improved method for the dehydrogenative C-H/C-H cross-coupling at the C-7 position of indolines containing a urea as a directing group is reported. The new protocol is a rare example of an aerobic palladium(II)-catalyzed cross dehydrogenative coupling (CDC) reaction that proceeds at low temperature. The use of either Cu(OAc)2 in an open flask or dioxygen (balloon) at 50 °C tolerates indolines not substituted at C-2 and C-3, thereby extending the scope of the previous method that suffers from indoline-to-indole oxidation.
RESUMEN
A mild procedure for C-7-selective C-H alkenylation of various indolines under oxidative palladium(II) catalysis is reported. A fully substituted urea, formed by carbamoylation of the indoline nitrogen atom, functions as a directing group. Both α,ß-unsaturated acceptors and styrenes participate in this direct C-H functionalization. With a free NH group at the urea terminus, the nitrogen atom subsequently cyclizes in a 1,4-fashion to yield a six-membered ring.