Metal-free synthesis of ketones by visible-light induced aerobic oxidative radical addition of aryl hydrazines to alkenes

Abstract

A green and cost-effective method has been developed for the conversion of alkenes to ketones under metal-free conditions.

A Visible‐Light‐Promoted Metal‐Free Strategy towards Arylphosphonates: Organic‐Dye‐Catalyzed Phosphorylation of Arylhydrazines with Trialkylphosphites

“…Based on the above‐mentioned results and literature reports,, a plausible mechanism for this visible‐light‐mediated reaction was proposed (Scheme ). First, EB is excited to form EB * in the presence of white LEDs light.…”

“…In contrast, organic dyes are an attractive alternative to the transition metal complexes as photoredox catalysis in that they are usually less expensive, less toxic, and easier to handle. [16] For example, the organic 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 dyes such as methylene blue, [17] eosins, [18] rhodamines, [19] etc. have been proved to be excellent visible-light photocatalysts in a number of synthetic reactions, represented by visible-light induced aerobic oxidative radical addition of aryl hydrazines to alkenes, [17a] cross-dehydrogenative coupling reaction [20] and visible-light photo-Arbuzov reaction [21] etc.…”

“…For example, the organic dyes such as methylene blue, eosins, rhodamines, etc. have been proved to be excellent visible‐light photocatalysts in a number of synthetic reactions, represented by visible‐light induced aerobic oxidative radical addition of aryl hydrazines to alkenes, cross‐dehydrogenative coupling reaction and visible‐light photo‐Arbuzov reaction etc.…”

Recent Advances in Photoredox Methods for Ketone Synthesis

“…Zhu and co‐workers in 2017 reported another efficient protocol for the synthesis of ketones via oxidative coupling of styrenes with aryl radicals sourced from phenylhydrazines under visible light (Scheme ) . The protocol employs metal free conditions to access diverse ketones.…”

Photochemical and electrochemical C–N borylation of arylhydrazines

“…Photochemistry 9–13 and electrochemistry 14–20 represent two environmentally benign strategies in organic synthesis. Arylhydrazines were reported to generate aryl radical species upon visible light irradiation 21–29 or anodic oxidation. 30 Recently, borylation reactions based on a radical mechanism have attracted considerable attention.…”