Pd-catalyzed oxidation of alkynes

Development of fluorinated benzils and bisbenzils as room-temperature phosphorescent molecules

“…This study was initiated with the synthesis of fluorinated bisbenzil derivatives. The PdCl 2 -catalyzed oxidation of the C≡C bonds in 1 by dimethyl sulfoxide (DMSO) was performed according to a previously reported procedure (Scheme 1) [33,34]. The methoxy-substituted fluorinated bistolane 1a was prepared from commercially available 4-ethynylanisole in four facile steps.…”

“…The proposed mechanism of Pd(II)-catalyzed C≡C oxidation is illustrated in Scheme 2 [33]: The catalytic cycle starts with the coordination of the electron-rich C≡C bond to the electron-deficient divalent Pd center, forming the corresponding π-complex (Int-A). Int-A smoothly undergoes nucleophilic attack by the oxygen atom in DMSO to construct a cationic vinyl-palladium(II) species (Int-B).…”

Oxidative cleavage of alkynes: a review of the methods invented so far and their application possibilities in green organic synthesis

“…was given by Muzart et al (figure 41). 186 CuX2, ZnX2 salts in DMSO were mostly used as additives, where X is halogen. The general reaction mechanism with the use of DMSO has been described in the publication by Gao et al based on diphenylacetylene assumed as followed (Figure 42).…”

Amino Acid-Catalyzed Direct Synthesis of β-Keto Sulfones via Aerobic Difunctionalization of Terminal Alkynes in an Aqueous Medium

“…37,38 The synthesis of β-keto sulfones involving radical sulfonylation approaches is either through activated alkenes or alkynes. 39,40 In this context, several industrial important processes have been developed, including hydroacylation of α,β-unsaturated esters, 41 Pdcatalyzed Wacker-type oxidation, 42 radical addition of Grignard reagents to olefins, 43 Sonogashira coupling, 44,45 autoxidative coupling reactions, 46,47 and metal-catalyzed reactions 48,49 61 Lipshutz's group also developed the synthesis of β-keto sulfones via an aerobic oxidation in nanomicelles using TPGS-750-M as the surfactant and 2,6-lutidine as the base from aryl alkynes and sulfinic salts, 62 and Yi Li et al reported a two-step synthesis of β-keto sulfones from aryl alkynes and sulfinic salts using rhodium(I) catalyst followed by a visible-light promoted photoredox via vinyl tosylates 63 (Scheme 1). However, all of these methods suffer from drawbacks such as the use of transition-metal catalysts, toxic reagents, and solvents like pyridine/substituted pyridine and chlorinated solvents, an excess amount of base, higher reaction temperature, longer reaction time, and low yield of products.…”

“…One of the most ideal strategies for the oxidative functionalization of organic molecules is with dioxygen, which is an environmentally benign, cost-effective oxidant and effectively used in dioxygenation, aminooxygenation, oxyalkylation, and oxyphosphorylation . β-Keto sulfones such as olefins, disubstituted alkynes, alkenes, chiral vinyl sulfones, and ketones , are important scaffolds and synthetic intermediates, which are key synthones for the synthesis of natural products such as lycopodine alkaloid, polyfunctionalized 4H-pyrans, quinolines, vinyl sulfones, and sulfonyl scaffolds. , The synthesis of β-keto sulfones involving radical sulfonylation approaches is either through activated alkenes or alkynes. , In this context, several industrial important processes have been developed, including hydroacylation of α,β-unsaturated esters, Pd-catalyzed Wacker-type oxidation, radical addition of Grignard reagents to olefins, Sonogashira coupling, , autoxidative coupling reactions, , and metal-catalyzed reactions , (sulfonylation via C–H bond activation followed by cross-coupling reactions). The formation of C–S bonds (e. g., sulfonylation that uses sulfonyl precursors) are well established in the synthesis of organosulfur compounds. − …”