Synthesis of 1,4‐Dicarbonyl Compounds by Visible‐Light‐Mediated Cross‐Coupling Reactions of α‐Chlorocarbonyls and Enol Acetates
作者:Qiang Liu、Rui‐Guo Wang、Hong‐Jian Song、Yu‐Xiu Liu、Qing‐Min Wang
DOI:10.1002/adsc.202000791
日期:2020.10.21
visible‐light‐mediatedradical coupling reactions of α‐chloroketones and enol acetates to afford 1,4‐dicarbonyl compounds, which are important precursors and intermediates in organic synthesis. The reaction involves photoredox‐catalyzed activation of the α‐chloroketone upon photoelectron transfer, carbon–chlorine bond cleavage, and coupling of the resulting radical with the carbon–carbon double bond of the
Radical alkylations of activated alkyl iodides and bromides were achieved usingvinyltriflates in the presence of hexadimethyltin, whereas those of unactivated C-H bonds usingvinyltriflates proceeded cleanly under tin-free conditions.
effective direct hydrogen‐atom transfer catalyst for C−H activation. Using the alkylation of C−Hbonds with electron‐deficient alkenes as a model study revealed an extremely broad substrate scope, enabling easy access to a variety of important synthons. This eosin Y‐based photocatalytic hydrogen‐atom transfer strategy is promising for diverse functionalization of a wide range of native C−Hbonds in a green
Cross-Coupling Reaction of α-Chloroketones and Organotin Enolates Catalyzed by Zinc Halides for Synthesis of γ-Diketones
作者:Makoto Yasuda、Shoki Tsuji、Yusuke Shigeyoshi、Akio Baba
DOI:10.1021/ja0258172
日期:2002.6.1
catalyzed by zinc halides. In contrast to the exclusive formation of 1,4-diketones 3 under catalytic conditions, uncatalyzed reaction of 1 with 2 gave aldol-type products 4 through carbonyl attack. NMR study indicates that the catalyzed reaction includes precondensation between tin enolates and α-haloketones providing an aldol-type species and their rearrangement of the oxoalkyl group with leaving halogen
Free radical-promoted one carbon ringexpansion and chain extension of 1,3-diketones including 1,3-diarylpropane-1,3-diones and 2-aroyl-3,4-dihydro-2H-naphalen-1-one to generate corresponding 1,4-diketones are described.