Silver-Catalyzed Diastereo- and Enantioselective Michael Addition and 1,3-Dipolar Cycloaddition Reactions of Imino Esters to 3-Methyl-4-nitro-5-styrylisoxazoles

Abstract

The AgOAc/ThioClickFerrophos complex catalyzed conjugate additions and 1,3-dipolar cycloadditions of 3-methyl-4-nitro-5-styrylisoxazoles with 1-pyrroline-5-carboxylates and glycine imino esters to give the corresponding Michael adducts and cycloadducts, respectively, in good yields with excellent diastereo- and enantioselectivities. These reactions can provide pyrroline- or pyrrolidine-containing isoxazole hybrid molecules that have potential biological and pharmaceutical activities.

Recent Developments in Highly Stereoselective Michael Addition Reactions Catalyzed by Metal Complexes

“…The catalytic system AgOAc/ThioClickFerrophos 72 has also been successfully used in the conjugate addition of 1-pyrroline-5-carboxylates 74 to 3-methyl-4-nitro-5styrylisoxazoles 84 in good yields and excellent diastereoand enantioselectivity (Scheme 22). 28 Scheme 22 Ag(I)/ThioClickFerrophos-catalyzed addition of 1-pyrroline-5-carboxylates and aldimino esters to 3-methyl-4-nitro-5-styrylisoxazoles 2-Oxazoline-and 2-thiazoline-4-carboxylates 86 also reacted with nitroalkenes in the presence of the same catalyst AgOAc/72 in excellent yields and with excellent enantio-and diastereoselectivities (Scheme 23). 29…”

Sustainable synthesis of highly diastereoselective & fluorescent active spirooxindoles catalyzed by copper oxide nanoparticle immobilized on microcrystalline cellulose

“…[36] Metallic nanoparticles have distinct qualities, particularly their large surface area, high stability, and easy separation, which makes them applicable to a wide range of catalytic applications. [37] Transition metals such as Sc, [38] Cu, [39][40][41] Zn, [19] Ni, [42] Ag, [43] and Ru [44] were employed as catalysts in organic synthesis for one-pot 1,3-dipolar cycloaddition. However, there exist a few drawbacks in the use of metal oxide nanoparticles like agglomeration, leaching, and poor recovery of catalysts.…”

Silver/ThioClickFerrophos-Catalyzed 1,3-Dipolar Cycloaddition and Tandem Addition–Elimination Reaction of Morita–Baylis–Hillman Adducts

“…Nitrogen-containing five-membered ring compounds have received significant attention because they are frequently found in various natural products and biologically active compounds (Figure ). Therefore, novel methods of preparing nitrogen-containing five-membered ring compounds with a high stereoselectivity have been developed. − Recently, imino esters have attracted increased attention for the construction of these scaffolds . Acyclic imino esters can be used for catalytic stereoselective 1,3-dipolar cycloaddition with electron-deficient alkenes, where this process efficiently affords pyrrolidine derivatives in one step .…”

“…Acyclic imino esters can be used for catalytic stereoselective 1,3-dipolar cycloaddition with electron-deficient alkenes, where this process efficiently affords pyrrolidine derivatives in one step . In addition, cyclic imino esters bearing five-membered ring structures, such as pyrroline esters, can be used as building blocks to which substituents can be introduced by stereoselective transformations such as Michael addition . Because these transformations can be widely applied to various electron-deficient alkenes, including acrylates, nitroalkenes, and vinyl sulfones, , they are suitable for the divergent synthesis of optically active pyrrolidine derivatives.…”