Base-mediated benzannulation of α-cyanocrotonates with ynones: facile synthesis of benzonitriles and fluorenes
作者:Maneesh Kumar Reddy Singam、Attunuri Nagireddy、Sridhar Reddy Maddi
DOI:10.1039/d0gc00608d
日期:——
Benzonitriles and cyanofluorenes have been rapidly obtained via the [3 + 3] benzannulation of readily available alkynones and α-cyanocrotonates using KOtBu as the only reagent and EtOH (and CO2) is the only by-product.
The metal-free oxidative alkene methylation/alkynylation of 1,4-enyn-3-ols with an organic peroxide as the methyl source has been developed, which provides straightforward and practical access to the challenging quaternary-carbon-containing but-3-yn-1-ones. The method is reasoned to go through methylation of functional alkenes utilizing dicumyl peroxide as the methylating reagent and subsequent intermolecular
3-exo-dig cyclization with 1,2-alkynyl migration of 1,4-enynes with simple cycloalkanes was established, enabling C–C breaking and reconstruction to access a wide range of α-alkynyl ketones with generally good yields by FeCl2/di-tert-butyl peroxide (DTBP) as a catalytic oxidation system. Radical-induced C(sp3)–H functionalization of cycloalkanes was realized, leading to the direct formation of C(sp3)–C(sp3)
Synthesis of benzoxazoles <i>via</i> the copper-catalyzed hydroamination of alkynones with 2-aminophenols
作者:Kohei Oshimoto、Hiroaki Tsuji、Motoi Kawatsura
DOI:10.1039/c9ob00572b
日期:——
describe herein the synthetic method to benzoxazole derivatives via the copper-catalyzed hydroamination of alkynones with 2-aminophenols. The method produced a wide variety of functionalized benzoxazole derivatives in good yields. Preliminary mechanistic experiments revealed that the reaction would proceed through the copper-catalyzed hydroamination of alkynones and the sequential intramolecular cyclization
A general two-step one-pot synthesis process of ynones from α-keto acids and 1-iodoalkynes
作者:Xiaobao Zeng、Chulong Liu、Weiguang Yang、Xingyong Wang、Xinyan Wang、Yuefei Hu
DOI:10.1039/c8cc05429k
日期:——
A general two-step one-pot synthesis process of ynones was developed by cycloaddition of α-keto acids and 1-iodoalkynes followed by a ring-opening reaction. Its easy conditions and novel mechanism endowed it with two distinctive advantages: iodine-atom bonded to C(sp2) remained intact and α-keto acids became a part of the triple bonds in ynones.