Reactions of RMgX . THF complexes with 4-chloro-2-methyl-3-butyn-2-ol in aromatic hydrocarbons were studied. The complexes formed by arylmagnesium halides require the presence of anisole for the reaction to occur. 4-Chloro-2-methyl-3-butyn-2-ol can be synthesized by reaction of 2-methyl-3-butyn-2-ol with sodium hypochloride in the two-phase system water-benzene.
A novel chloropalladation-initiated intermolecular oxyvinylcyclization of alkenes with alkynoic acids or alkynols is developed. This protocol provides a series of 3-methylene γ-lactone and tetrahydrofuran derivatives in moderate to excellent yields with high stereoselectivities in the presence of PdCl2 and CuCl2 or CuCl2·2H2O. Besides a broad substrate scope, this method has the advantages of mild
Rh(III)-Catalyzed Regioselective Annulations of 3-Arylisoxazolones and 3-Aryl-1,4,2-dioxazol-5-ones with Propargyl Alcohols: Access to 4-Arylisoquinolines and 4-Arylisoquinolones
The Rh(III)-catalyzed dual directing group assisted C–H activation/annulation of 3-arylisoxazolones with propargyl alcohols has been developed, which expands the application scope of isoxazolones in organic synthesis. This protocol also worked well with 3-aryl-1,4,2-dioxazol-5-ones to produce synthetically and biologically important 4-arylisoquinolones.
Palladium-Catalyzed Arylcarboxylation of Propargylic Alcohols with CO<sub>2</sub> and Aryl Halides: Access to Functionalized α-Alkylidene Cyclic Carbonates
trans-oxopalladation of the C≡Cbond by an ArPdX species, and a reductive elimination procedure afforded a series of functionalized α-alkylidene cyclic carbonates in moderate to excellent yields. Notably, the configuration of these tetrasubstituted olefins was dominated by the trans-oxopalladation step where the aryl group derived from ArX is located trans to the oxygen attached in the doublebond. This protocol
propargyl carbonates have been developed by using two O-containing functional groups as the traceless assisting groups (AGs). The experimental investigations together with the density functional theory (DFT) calculations revealed that this transformation involves the free OH-directed cleavage of one terminal C–H bond of the alkenyl moiety and regioselective alkyne insertion, followed by OBoc-promoted intramolecular
Practical synthesis of aryl-2-methyl-3-butyn-2-ols from aryl bromides via conventional and decarboxylative copper-free Sonogashira coupling reactions
作者:Andrea Caporale、Stefano Tartaggia、Andrea Castellin、Ottorino De Lucchi
DOI:10.3762/bjoc.10.36
日期:——
efficient protocols for the palladium-catalyzedsynthesis of aryl-2-methyl-3-butyn-2-ols from arylbromides in the absence of copper were developed. A simple catalytic system consisting of Pd(OAc)2 and P(p-tol)3 using DBU as the base and THF as the solvent was found to be highly effective for the coupling reaction of 2-methyl-3-butyn-2-ol (4) with a wide range of arylbromides in good to excellent yields