of catalytic amounts of optically active aminoalcohols, the irradiation of α-disubstituted indanones, tetralones and propiophenones bearing at least one hydrogen in the γ-position led to Norrish type II cleavage compounds which were obtained with enantiomeric excesses reaching 89%. The influence of the reaction conditions (temperature, wavelength of the UV light and nature of the alcohol) has been analyzed
α-Aminoxy-Acid-Auxiliary-Enabled Intermolecular Radical γ-C(sp<sup>3</sup>
)−H Functionalization of Ketones
作者:Heng Jiang、Armido Studer
DOI:10.1002/anie.201712066
日期:2018.2.5
site‐specific intermolecular γ‐C(sp3)−H functionalization of ketones has been developed using an α‐aminoxy acid auxiliary applying photoredox catalysis. Regioselective activation of an inert C−H bond is achieved by 1,5‐hydrogen atom abstraction by an oxidatively generated iminyl radical. Tertiary and secondary C‐radicals thus formed at the γ‐position of the imine functionality undergo radicalconjugate addition
Expedient Synthesis of Ketones
<i>via</i>
<scp>
<i>N</i>
‐Heterocyclic
</scp>
Carbene/
<scp>Nickel‐Catalyzed Redox‐Economical</scp>
Coupling of Alcohols and Alkynes
<sup>†</sup>
作者:Yu‐Qing Li、Feng Li、Shi‐Liang Shi
DOI:10.1002/cjoc.202000019
日期:2020.10
N‐heterocyclic carbene/nickel‐catalyzed direct coupling of alcohols and internal alkynes to form α‐branched ketones has been developed. This methodology provides a new approach to afford branched ketones, which are difficult to access through the hydroacylation of simple internal alkenes with aldehydes. This redox‐neutral and redox‐economical coupling is free from any oxidative or reductive additives
The O-alkoxycarbonylation of lithiumenolates of α-disubstituted aryl ketones was selectively obtained when the enolates, prepared in using lithium bis(trimethylsilyl)amide, were added to chilled THF solutions of allyl or benzyl chloroformates.
Organocatalytic C−H Functionalization of Simple Alkanes
作者:Fen Su、Fengfei Lu、Kun Tang、Xiaokang Lv、Zhongfu Luo、Fengrui Che、Hongyan Long、Xingxing Wu、Yonggui Robin Chi
DOI:10.1002/anie.202310072
日期:2023.11.6
functionalization/acylation of strong aliphatic C(sp3)-H bonds is disclosed via an N-heterocyclic carbene (NHC)-catalyzed dehydrogenative coupling of aldehydes with simple alkanes. The inert aliphatic C−H bonds are efficiently cleaved through intermolecular hydrogen atom transfer, providing an alternative organocatalytic approach for alkane C−H functionalization under transition metal- and light free