| Carbonyl compounds are generally an important class of basic organic chemicals, which are widely applied in the fields of material science, information science, pharmaceutical industry, food chemistry, and so on. The transition metal catalyzed carbonylation reactions of organic substances with carbon monoxide(CO) constitute one of the most straightforward methods for the synthesis of carbonyl compounds in an atom-economic fashion. Among them, palladium-catalyzed CO-involved carbonylation reactions have attracted considerable attention owing to the merits of high catalytic efficiency and excellent selectivity.Vinyl sulfones posses some unique bioactivities and widely occur in many pharmaceuticals and agrichemicals, such as inhibitors as well as pesticides and herbicides. For example, substituted vinyl sulfones have proved to be potent inhibitors of a variety of enzymatic processes, which mainly include inducible VCAM-1 expression inhibition and cysteine proteases. Hence, they have been applied for designing candidate drugs as the new enzymatic inhibitors, and received overwhelming attention in the pharmaceutical industry.On the basis of the above-described background, we have performed the investigations of palladium-catalyzed carbonylation reaction for the synthesis of cyclopentadienone and nitrogen-containing carbonyl compounds, the desulfurization and decarboxylation of oxidative coupling reaction for the synthesis of substituted vinyl sulfones compounds under the guidance of green chemistry’s principles, which consists of the following four sections:In chapter 2, a convenient and efficient synthesis of cyclopentadinones via palladium-catalyzed [2+2+1] cyclocarbonylation of alkynes is reported. The electronegativity of functional groups of alkynes could lead to different substituted cyclopentadinones products. The synthetic protocol has the advantages of mild reaction conditions, no need for ligands, wide substrate scopes, easily available starting materials, making this atom-economical [2+2+1] cyclocarbonylation reaction possessing excellent application prospects.In chapter 3, a highly selective palladium-catalyzed carbonylation of C(sp2)-H bonds of aromatic oximes for the synthesis of benzo[d][1,2]oxazin-1-ones and(Z)-3-methyleneisoindolin-1-ones is reported. The N-OH group of the oximes could act as a directing group and/or an internal oxidant under different conditions. This transformation consists of a hydroxyl-directed ortho-C(sp2)–H oxidative carbonylation reaction and another one of vinyl C(sp2)–H bond/ortho-C(sp2)–H bond. The only byproduct is water, and the mild reaction conditions, providing a rapid and efficient access to nitrogen-containing carbonyl compounds.In chapter 4, a highly efficient and mild palladium-catalyzed cross-coupling of sodium sulfinates and alkynes for the selective synthesis of unsymmetrical internal alkynes and vinyl sulfones has been described. On the one hand, the reaction of sodium sulfinates and terminal alkynes giving the internal alkynes products with releasing SO2, in which no copper or silver additives were added, and has the advantages of excellent selectivities and high yields. On the other hand, sodium sulfinates could be used as a sulfone reagent, reacting with terminal alkynes lead the formation of C-S bonds, which have a broad substrate scope, mild reaction conditions, as well as high atom efficiency.In chapter 5, a novel transition metal-free synthesis of vinyl sulfones through K2CO3-promoted cross-decarboxylative coupling reaction of sodium sulfinates and cinnamic acids is reported. The DMSO is used as both the solvent and the oxidant in the reaction system, no need to other oxidants. The only byproduct is CO2, and this protocol has the advantages of features inexpensive starting materials, easy to operate and environmental benign, as well as exceptional functional group tolerance, providing a simple and efficient approach for the synthesis of vinyl sulfones. |
PDF Full Text Request