Eosin Y as a Direct Hydrogen‐Atom Transfer Photocatalyst for the Functionalization of C−H Bonds

Abstract

Eosin Y, aw ell-known economical alternative to metal catalysts in visible-light-driven single-electron transferbased organic transformations,c an behave as an effective direct hydrogen-atom transfer catalyst for CÀHa ctivation. Using the alkylation of C À Hb onds with electron-deficient alkenes as amodel study revealed an extremely broad substrate scope,enabling easy access to avariety of important synthons. This eosin Y-based photocatalytic hydrogen-atom transfer strategy is promising for diverse functionalization of aw ide range of native CÀHbonds in agreen and sustainable manner.

Neutral‐Eosin‐Y‐Photocatalyzed Silane Chlorination Using Dichloromethane

“…[4] Additionally,w er ecently disclosed the unique property of neutral eosin Y, which can function as an ideal direct HATp hotocatalyst owing to its visible-light-absorption, metal-free,r eadily available,a nd low-cost nature. [5] It has been applied to the CÀHalkylation, which accommodates an extremely broad substrate scope owing to no limitation on redox potentials. [5] In view of the electrophilic nature of the oxygen radical in the photoexcited eosin Ytriplet state,itwas anticipated that this catalytic HATp rocedure might be extended to abstraction of protons from hydridic Si À H bonds,t oa ccess transient and reactive silyl radicals for the synthesis of value-added silicon reagents.…”

“…[5] It has been applied to the CÀHalkylation, which accommodates an extremely broad substrate scope owing to no limitation on redox potentials. [5] In view of the electrophilic nature of the oxygen radical in the photoexcited eosin Ytriplet state,itwas anticipated that this catalytic HATp rocedure might be extended to abstraction of protons from hydridic Si À H bonds,t oa ccess transient and reactive silyl radicals for the synthesis of value-added silicon reagents. [6] Chlorosilanes are widely used reagents in organic chemistry and material science.T hey are extensively utilized in multistep organic synthesis for the installation of silyl protecting groups on alcohols,a mines,a cids,a nd alkynes.…”

Poly(vinylidene difluoride) Membrane Assisted by Modified ZnO/ZIF Nanoparticles for Membrane Distillation

“…The inlet temperatures at the feed and permeate sides ranged from 60°C to 83°C and 20°C to 25°C, respectively, which were continually monitored [30,35]. The flow rates on the feed and permeate sides were fixed at 400 and 200 mL h -1 , respectively, because the permeate flux was dependent on the flow rate of the feed stream and the effect of the flow rate of the feed stream was larger than that of the permeate stream [36]. The MD permeate flux was calculated according to Eq.…”

Visible‐Light‐Mediated Metal‐Free Difunctionalization of Alkenes with CO2 and Silanes or C(sp3)−H Alkanes

“…We envisioned that the incorporation of an electrophile such as CO 2 in the reaction mixture might enable difunctionalization of alkenes over the competing protonation, and produce b-silacarboxylic acids. [ However, the use of transition metals,s trong bases or prefunctionalized radical precursors are required in these reaction systems.A s part of our continuing interests in developing visible-lightpromoted transformations using inexpensive gaseous feedstocks [11] and readily available C(sp 3 ) À Ha nd Si À Hb onds as latent nucleophilic handles, [7,12] we herein report the first silacarboxylation of simple alkenes using CO 2 and silanes through the synergistic combination of an organic photoredox catalyst and aH AT catalyst. [8] However,c onsiderable advances of functionalization of alkenes with CO 2 are confined to hydrocarboxylation, [9] and difunctionalization of alkenes with CO 2 is quite rare.…”