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Tosylates, cross-coupling

Several metal cross-coupling reactions have been applied to pyrazoles. C-H Arylation of aryl tosylates or chlorides could be achieved with a ruthenium catalyst at the C-2 phenyl position of... [Pg.212]

This route involves the conversion of a 3,4-diiodopyrrole (139) to the corresponding 3,4-diboronate ester (140) followed by a bis Suzuki cross-coupling reaction with a bromoquinoline, which generates the halitulin core (141). This pyrrole (141) is then alkylated with a tosylated cycloazadecane to generate a pentasubstituted pyrrole (143), which is converted to halitulin by debenzylation under hydrogenolysis conditions. [Pg.102]

The 2-formyl-ip-methylcarbapenem 62 has been obtained in five steps from a readily available P-lactam in 23-26% overall yield <98MI1294>. Suzuki-Miyaura cross-coupling of aiylboronic acids and vinyl triflates is a convenient route to 2-aiylcarbapenems on a small scale but may present problems on a large scale. Vinyl phosphates, mesylates or tosylates are convenient alternatives to triflates <9981471>. Radical cyclizations of readily available enyne-2-azetidinones (e.g., 63) with a tin hydride, RjSnH, provides a route to the... [Pg.85]

TABLE 6. Cross-coupling between alkyl Grignard reagents and aryl or heteroaryl chlorides, triflates, and tosylates... [Pg.612]

The Suzuki coupling of aryl halides was also extended to tosylates recently. Benzothiazole 5-tosylate reacted with m-xylene-2-boronic acid (6.13.) to give the coupled product in 94% yield using palladium acetate and a stericly congested biphenyl based phosphine ligand as catalyst.17 Another class of less commonly utilised cross-coupling partners are methyltio derivatives. In the presence of a copper salt, which activates the carbon-sulphur bond, 2-methyltio-benzotiazol coupled readily with a series of arylboronic acids.18... [Pg.102]

The same group developed an interesting intermolecular palladium-catalyzed alienation of aryliodide with N-tosyl o-iodoanilines with nucleophiles in combination with two palladium-coupling reactions [69]. In this reaction, the N-allyl(2-iodopalladium)aniline intermediate 52 underwent an intramolecular Heck reaction followed by a cross-coupling reaction with phenyl boronic acid to give the 3,3-disubstituted indoline 53 in 78% yield (Scheme 8.27). [Pg.238]

Alkylpalladium complexes generated by oxidative addition of Pd(0) to alkyl halides with a /3 hydrogen can undergo /3-elimination to yield an alkene and a Pd-hydrido complex (as in the Heck reaction Scheme8.7). Nevertheless, this process is relatively slow compared with transmetalations and reductive eliminations, and simple alkyl halides or tosylates with /3 hydrogen can be cross-coupled with carbon nucleophiles under optimized conditions if the nucleophile is sufficiently reactive [9, 73-75] (Scheme8.6). [Pg.284]

Zhou, J. Fu, G. C. Palladium-catalyzed Negishi cross-coupling reactions of unactivated alkyl iodides, bromides, chlorides, and tosylates. I. Am. Chem. Soc. 2003, 125, 12527-12530. [Pg.304]

Introduction of the silylmethyl group into organic halides, tosylates, and epoxides is achieved by nickel, palladium-, or copper-catalyzed cross-coupling reactions. [Pg.226]

One of the challenges in the Suzuki-type cross-coupling is to extend this reaction from electron-rich aryl iodides, bromides, and triflates to less reactive aryl sulfonates and aryl chlorides, which show poor reactivity in terms of oxidative addition in the catalytic cycle. Aryl mesylates, benzenesulfonates, and tosylates are much less expensive than triflates, and are unreactive toward palladium catalysts. The Ni(0)-catalyzed Suzuki-type cross-coupling reaction of aryl sulfonates, including mesylates, with arylboronic acids in the presence of K3P04 has been reported [123]. [Pg.93]


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See also in sourсe #XX -- [ Pg.137 ]




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Tosylate coupling

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