Visible‐Light‐Enabled Selective Oxidation of Primary Alcohols through Hydrogen‐Atom Transfer and its Application in the Synthesis of Quinazolinones

Abstract

A visible-light-enabled selective oxidation of alcohols to aldehydes has been developed under transitionmetal-free conditions. Utilizing eosin Y as the direct hydrogen-atom transfer (HAT) photocatalyst and molecular oxygen as the terminal oxidant, both aromatic and aliphatic aldehydes could be obtained in moderate to good yields. Using this approach, various quinazolinones, including two real drug molecules, were easily synthesized from the corresponding o-aminobenzamides and alcohols. Scheme 1. Visible-light-enabled selective oxidation of alcohols to aldehydes and synthesis of quinazolinones from alcohols and o-aminobenzamides.

Visible Light-Induced Aerobic Oxidative Dehydrogenation of C–N/C–O to C=N/C=O Bonds Using Metal-Free Photocatalysts: Recent Developments

“…Additionally, other xanthene-related photocatalysts used were Eosin Y (3, 1 mol%), which promoted the oxidation of aromatic and long-chain aliphatic primary alcohols to aldehydes 69 in moderate to good yields under O2 atmosphere (balloon) and irradiated with a 50 W Xe lamp [164]. Thioxanthone (5-20 mol%) also successfully catalyzed the oxidation of aromatic and aliphatic primary and secondary alcohols (including cinnamyl alcohol, 1,3-diphenylpropargylalcohol, xanthenol, ciclohexanol, borneol, menthol and The flavinium salt 71 (5 mol%) was also recently employed in the oxidative dehydrogenation of aromatic secondary alcohols to render ketones using cesium carbonate (CsCO 3 , 70 mol%) as additive, O 2 (balloon) as oxidant and under blue light irradiation, obtaining good yields [159].…”

Eosin: a versatile organic dye whose synthetic uses keep expanding

“…In 2019, Xia et al published a novel methodology for the synthesis of quinazolinones of type 108 (Scheme 26). 44 Quinazolinones are common in both natural products and drugs, indeed, two drugs are synthesized in the paper. In a process with broad scope, it is proposed that eosin initiates the reaction sequence by abstracting one of the hydrogen atoms (*EY → • EY-H) from adjacent to the alcohol functionality in 106.…”

Photoinduced Enhanced Decomposition of TBHP: A Convenient and Greener Pathway for Aqueous Domino Synthesis of Quinazolinones and Quinoxalines

“… 27 , 28 Various photocatalysts, such as Ru(II)- and Ir(III) metal-based molecular systems, dyes, and semiconducting nanoparticles, have been developed for visible light-catalyzed organic transformations. 29 − 35 Recently, N-hydroxyphthalimide (NHPI) has been developed as an effective organophotoredox catalyst for cyclization reactions. 36 TBHP is well-known to form free radicals at elevated temperatures through the homolysis of the O–O bond, which is potentially used for the oxidation of benzylic alcohol and the C–H bond.…”