Intramolecular Wittig reaction of α,α′-dioxocycloalkylidenetributylphosphoranes: formation and trapping of cycloalkyn-2-ones with five- and six-membered rings
Reaction of the title phosphoranes with homophthalic anhydride or 1,3-diphenylisobenzofuran in the presence of Me3SiCl gave the corresponding Diels–Alder adducts, indicating the transient intermediacy of cycloalkyn-2-ones with five- and six-memberedrings.
A One-Pot Synthesis of Pyranone and Pyrrole Derivatives from β-Chlorovinyl Ketones via Direct Conjugate Addition Approach
作者:Hun Young Kim、Kyungsoo Oh
DOI:10.1021/acs.orglett.7b02381
日期:2017.9.15
The direct conjugate addition reactions of imino esters to β-chlorovinyl ketones have been accomplished in the presence of a substoichiometric amount of hard base, LiHMDS. An in situ generated species from the conjugate addition reaction readily acted as autocatalyst to convert the imino esters to its corresponding enolates. By utilizing a sequence of conjugate addition/elimination/lactonization followed
Gallium chloride catalyzed acylation of alkynes was studied to afford one of the most atom-economic and efficient methodologies for the preparation of β-chlorovinyl ketones. In contrast to the Friedel-Crafts acylation, only a catalytic amount of GaCl3 was needed to produce the target products in high stereoselectivity.
Straightforward synthesis of alkynyl imines via 1,2-elimination of α,α-dichloroketimines
作者:Sven Mangelinckx、Stijn Rooryck、Jan Jacobs、Norbert De Kimpe
DOI:10.1016/j.tetlet.2007.07.047
日期:2007.9
bromides afforded β-arylated α,α-dichloroketimines in good yields. The latter imines could be easily transformed to the corresponding alkynyl imines, a synthetically important class of compounds, via 1,2-elimination of HCl upon treatment with 2 equiv of sodium hydride in DMSO or potassium tert-butoxide in THF.