Pd-Catalyzed Sequential Formation of C–C Bonds: A New Strategy for the Synthesis of (E)-α,β-Unsaturated Carbonyl Compounds from Sulfoxonium Ylides and 1-Iodo-2-((2-methylallyl)oxy)benzene Compounds

Abstract

α,β-Unsaturated carbonyl compounds are significant moieties in many biological molecules and have attracted considerable attention in organic synthetic chemistry. A Pd-catalyzed cascade cyclization for the synthesis of (E)-α,β-unsaturated carbonyl compounds with the sequential formation of C−C bonds was developed. This method offers high efficiency, good functional group tolerance, and moderate to excellent yields and generally displays high stereoselectivity.

Oxygen-, Nitrogen-, and Sulfur-Containing Heterocycles: Recent Advances in De Novo Synthesis and Prospect

“…In continuation with our research interest in the transformation of alkyl-Pd species, we have developed some interesting kinds of palladium-catalyzed cascade processes for the construction of functionalized dihydrobenzofurans in recent years (Scheme 18). The oxidation addition of 1-iodo- 2-((2-methylallyl)oxy)benzene (50) and subsequently intramolecular insertion of alkene into the C(sp 2 )−Pd bond led to the alkyl-Pd intermediate Int-31, which then can be captured with N-tosylhydrazones, 33 sulfoxonium ylides, 34 or CO and alkyne 35 and smoothly transformed into diverse 3,3-difunctionalized benzofurans in moderate to good yields. In recent years, the phenol linked 1,n-enynes have been recognized as highly versatile substrates that allow for the construction of benzofurans or dihydrobenzofuran derivatives with structural diversity and complexity.…”

Rh(iii)-catalyzed C–H annulation of sulfoxonium ylides with iodonium ylides towards isocoumarins

“…Transition-metal-catalyzed directed group-assisted C–H bond activation has the merit of being able to construct complicated molecules efficiently, leading to rapid progress in the synthetic community over the decades. 9 In this field, the transition metal (Rh, 10 Ru, 11 Pd 12 and others 13 ) catalyzed C–H functionalization of arenes and coupling with sulfoxonium ylides holds great potential to manufacture various heterocycles. Sulfoxonium ylides have been predominantly used as carbonylation reagents 14 or C2 15 synthons in annulation reactions, usually as C4 16 synthons and occasionally as C3 17 synthons.…”

Palladium-catalyzed Heck cyclization/allylation with homoallyl alcoholsviaretro-allylation

“…4 The domino sequence involves intramolecular carbopalladation of olefins affording active σ-alkylpalladium species, which can be further functionalized. Since Grigg's seminal contributions, this strategy has been extensively studied by Zhu, Lautens, Zhang, Li, Gu, Jia, Chen and other groups, and (hetero)arylation, 5 alkenylation, 5 e , j ,6 alkynylation, 7 alkylation, 5 j ,8 iodination, 9 cyanation, 10 carboxylation, 7 e ,11 phosphorylation, 12 hydrogenation 13 and borylation 14 of σ-alkylpalladium have been achieved. Although significant achievements have been made in palladium-catalyzed aryl halide-tethered alkene cyclization/functionalization, to the best of our knowledge, allylation of σ-alkylpalladium has rarely been explored.…”