Visible-Light-Induced Multicomponent Synthesis of γ-Amino Esters with Diazo Compounds

Abstract

A visible-light-induced multicomponent reaction of ethyl diazoacetate, diarylamines, and styrene-type alkenes is described. This novel 1,2-difunctionalization of alkenes can be readily achieved under a simple operation and mild conditions, affording γ-amino esters as major products. The reaction proceeds through the generation of carbon-centered radicals from diazo compounds by a visible-light-promoted proton-coupled electron transfer (PCET) process. The carbon radicals then add to diverse alkenes, delivering new carbon radical species, and the final products are formed with N-centered radicals via a radical−radical coupling.

Iron-catalyzed ring-opening of cyclic carboxylic acids enabled by photoinduced ligand-to-metal charge transfer

“…16 This would lead to ring opening and the formation of 1, n -dicarbonyl products regardless of the ring size of substrates. As part of our ongoing interest in photochemical reactions, 17 we report herein a catalytic strategy for LMCT of iron complexes that allows an oxidative ring-opening of cyclic tertiary carboxylic acids to proceed smoothly under 390 nm LED light irradiation.…”

Cu-Catalyzed C(sp3)–N Coupling and Alkene Carboamination Enabled by Ligand-Promoted Selective Hydrazine Transfer to Alkyl Radicals

“…Theoretically, it is also possible to forge a C (sp3) –N bond through radical-radical cross-coupling if the N-nucleophile could be 1e-oxidized by Cu II . Nevertheless, because the electron negativity of nitrogen is higher than that of carbon, N-centered radicals are typically perceived as highly reactive species that are not easy to generate through 1e-oxidation under copper catalysis, and the cross-coupling selectivity between two transient radicals could also be challenging . Fortunately, in addition to their own structures, aminyl radicals are also known to be stabilized by coordinating to transition metals, such as Pd, Mn, Co, Ni, and Cu, , which could effectively facilitate the 1e-oxidation step.…”

Indolization of N-Aryl Tertiary Amines with Diazoacetates by a Single Organophotocatalyst

“…Therefore, the development of new strategies and exploration of further modes of reactivity of diazoacetates to overcome the limitations of previous processes are still very important. The advent and development of visible-light photoredox catalysis have provided a widely applicable radical formation strategy. − Herein, we have introduced an open-shell approach that employs the radical reactivity of diazoacetates to synthesize indoles for the first time (Figure C). Moreover, this visible-light-driven indolization of N -aryl tertiary amines is enabled by a single organic dye, 4CzIPN [4CzIPN = 1,2,3,5-tetrakis­(carbazol-9-yl)-4,6-dicyanobenzene], proceeding without metals or additives.…”