General and Efficient Insertions of Carbons Carrying Aryl and Heteroaryl Groups: Synthesis of α-Aryl- and α-Heteroaryl-Substituted Ketones
作者:Alan R. Katritzky、Dorin Toader、Linghong Xie
DOI:10.1021/jo960841h
日期:1996.1.1
iazoles 1 with n-BuLi underwent addition to aliphatic and aromatic aldehydes and cyclic and acyclic ketones. Subsequent in situ thermal rearrangements of the intermediates in the presence of zinc bromide provided one-carbon chain-extended or ring-expanded alpha-aryl- and alpha-heteroaryl-substituted ketones 2 in moderate to excellent yields in simple one-pot operations with excellent regioselectivity
enolizable ketones has been developed by using β-bromostyrenes and a KOtBu/NMP system. β,γ-Unsaturated ketones of E configuration were obtained in excellent yield and selectivity. Further synthetic possibilities are highlighted by one-pot functionalization via trapping of intermediate dienolates with alkyl, allyl, benzyl, and propargyl halides to generate quaternary centers. The reported transformation is
通过使用β-溴苯乙烯和KO t Bu / NMP系统开发了可烯化酮的α-乙烯基化。以优异的产率和选择性获得了E构型的β,γ-不饱和酮。通过一锅功能化,通过用烷基,烯丙基,苄基和炔丙基卤化物捕获中间二烯酸酯以生成季中心,进一步突出了合成的可能性。据信所报道的转化涉及苯乙炔和炔丙醇衍生物。
Selective C-C Bond Scission of Ketones via Visible-Light-Mediated Cerium Catalysis
作者:Yilin Chen、Jianbo Du、Zhiwei Zuo
DOI:10.1016/j.chempr.2019.11.009
日期:2020.1
catalytic manifold for the selectiveC–Cbond scission of ketones via the exploitation of the ligand-to-metal charge transfer (LMCT) excitation mode. Through a cooperative utilization of Lewis acid catalysis and LMCT catalysis, the C–Cbond of ketones could be selectively and effectively cleaved, enabling the installation of different functionalities at each carbon of the cleaved C–Cbond through a sequential
to representative classes of carbon electrophiles (i.e., vinyl sulfones, nitroolefins, formaldehyde) is documented. We demonstrate that by using selected chiral tertiary amine/squaramide catalysts, the reactions of β,γ‐unsaturated cycloalkanones proceed through the dienolate Cα almost exclusively and provide all‐carbon quaternary cyclic ketone adducts in good yields with very high enantioselectivities
Direct Asymmetric Amination of α-Branched Cyclic Ketones Catalyzed by a Chiral Phosphoric Acid
作者:Xiaoyu Yang、F. Dean Toste
DOI:10.1021/jacs.5b00229
日期:2015.3.11
Here we report the direct asymmetric amination of α-substituted cyclic ketones catalyzed by a chiralphosphoricacid, yielding products with a N-containing quaternary stereocenter in high yields and excellent enantioselectivities. Kinetic resolution of the starting ketone was also found to occur on some of the substrates under milder conditions, providing enantioenriched α-branched ketones, another