Asian Journal of Organic Chemistry最新文献

We have developed a convenient and modern method for obtaining amidoximes from aryl- or heteroaryl nitriles and hydroxylamine hydrochloride in the presence of a base using mechanochemical activation of the starting compounds. The method does not require the use of large volumes of solvents; the reaction occurs at room temperature for 2 h and provides high isolated yields of the corresponding amidoximes for most of the nitriles studied. We were also the first to use a mechanochemical approach to modify polysiloxanes. We demonstrated the possibility of synthesizing a functionalized copolysiloxane containing amidoxime functions and showed that the use of mechanochemical activation allows one to overcome one of the fundamental difficulties encountered by synthetics in the functionalization of polysiloxanes—reaction heterogeneity.

Trifluoromethylated internal alkynes are presented as a class of versatile building blocks for efficient assembly of various trifluoromethyl group-containing useful organic molecules through either direct nucleophilic addition or cyclization. Therefore, it has attracted significant attention from organic synthetic chemists and tremendous efforts have been devoted to the development of its rapid preparation. In this review, we aim to provide a comprehensive summary of the latest advances in the straightforward preparation of trifluoromethylated internal alkynes. We would also like to spur the recent discoveries and developments of innovative reaction paradigms in this field. Additionally, crucial challenges and future perspectives on this hot topic are also discussed, with the wish to provide a profound insight for not only future organofluorine chemistry but also fluorine-containing pharmaceutical science. This manuscript mainly focuses on the direct synthetic methodology to construct various unsymmetrical trifluoromethylated internal alkynes, and it is categorized according to various synthetic methods as well as different types of trifluoromethyl source.

We have developed a synthetic method for the asymmetric [3+2] cyclization to synthesize chiral 2,3-dihydrofurans using a novel diSaBOX ligand. The Hammett equation and kinetic experiments were employed to reveal the influence of different substituents on the side arm of the diSaBOX ligand on the enantioselectivity and reaction rate of the reaction. This method exhibits good functional group tolerance and can modify a variety of biologically active molecules. The reaction mechanism of this palladium-catalyzed [3+2] cyclization was further clarified through nonlinear experiments and intermolecular competition experiments.

An unusual pyrrole by-product formation has been discovered during the synthesis of pyrrolo[1,2-a]imidazole from imidazolium bromides and electron-deficient acetylenes. The methodology proceeds smoothly under mild conditions, affording 5-benzoyl-pyrrolo[1,2-a]imidazole derivatives in moderate-to-good yields. Interestingly, the study revealed an unusual side reaction: moisture-mediated ring opening of the imidazole nucleus, leading to pyrrole derivatives through an enamine hydrolysis pathway. Substrate scope investigations highlighted a striking selectivity while phenacyl bromides furnished both pyrrolo[1,2-a]imidazoles and pyrroles, 2-bromoacetonitrile derived imidazolium bromide (9) exclusively yielded pyrrole by-product as a major (12b and 13b) suggesting the nitrile group plays a decisive role in product distribution.

Oxygen-containing heterocycles are increasingly recognized for their biological significance, especially in the field of drug discovery. Therefore, the enantioselective synthesis of these frameworks has become a central focus in modern organic chemistry, inspiring the development of numerous elegant synthetic strategies over the past few decades. Among the various building blocks available, γ- and δ-hydroxy-α,β-unsaturated carbonyl compounds–bearing both an oxygen-centered nucleophile and a Michael acceptor–have emerged as highly versatile synthons for the efficient construction of oxygen-containing heterocycles through cascade annulation reactions. This review summarizes recent advances in the chemistry of these compounds, with particular emphasis on γ-hydroxy-α,β-unsaturated ketones, δ-hydroxy-α,β-unsaturated ketones, o-hydroxyphenyl-α,β-unsaturated ketones, and o-hydroxy-cinnamaldehydes, highlighting their applications in the enantioselective synthesis of diverse chiral oxygen-containing heterocycles via organocatalytic cascade reactions.

An environmentally benign electrochemical reductive method has been developed for the hydroselenization/hydrosulfuration of vinyl sulfones with diselenides/disulfides. The reaction proceeds smoothly in an undivided cell at room temperature in open air, without the need for metal catalysts or oxidants, achieving yields of up to 99% for 37 β-selenosulfones and β-thiosulfones. This strategy is also applicable to other electron-deficient olefins, providing a mild and efficient approach for constructing C─Se and C─S bonds.