The effect of thallium (I) salts on palladium catalysed tandem cyclisation-anion capture processes.

Grigg, Ronald; Loganathan, V.; Sukirthalingam, Sukanthini; Sridharan, Visuvanathar

doi:10.1016/s0040-4039(00)97120-x

Cited by 66 publications

(16 citation statements)

References 14 publications

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“…[20] For selective internal arylation of vinyl ethers with aryl iodides or bromides for which cationic organopalladium intermediates are required as intermediates, thallium salts are utilized as additives. [34] Although the role of the thallium additives [87]- [90] (or silver additives) [91]- [96] has not been fully elucidated, it is likely that these additives act as halide sequestering agents. Upon addition of thallium acetate, the halide ion in the oxidative addition complex is replaced by the acetate (X ϭ OAc).…”

Section: Bv Insertion Via Charged and Neutral -Complexesmentioning

confidence: 99%

Intermolecular Heck Reaction: Scope, Mechanism, and Other Fundamental Aspects of the Intermolecular Heck Reaction

Larhed

Hallberg

Handbook of Organopalladium Chemistry for Organic Synthesis

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Section: Bv Insertion Via Charged and Neutral -Complexesmentioning

confidence: 99%

Intermolecular Heck Reaction: Scope, Mechanism, and Other Fundamental Aspects of the Intermolecular Heck Reaction

Larhed

Hallberg

Handbook of Organopalladium Chemistry for Organic Synthesis

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“…The active catalyst is actually believed to be nanodispersed palladium metal generated by reduction of the catalyst precursor by ethanol under basic conditions 3) ( Table 8.5). The impact of silver(I) and thallium(I) salts [221] on Pd-catalyzed reactions extends beyond just increasing regioselectivities and enhancing reaction rates [202]. Without these additives, the arylation of allyl alcohols 27 afforded aldehydes and ketones 30, rather than the β-arylallyl alcohols 33 (Scheme 8.7).…”

Section: Effects Of Bases Ligands and Additivesmentioning

confidence: 99%

Cross‐Coupling of Organyl Halides with Alkenes – The Heck Reaction

Bräse¹,

Meijere²

2013

Metal‐Catalyzed Cross‐Coupling Reactions and More

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The carbopalladation of an alkene by an organylpalladium halide is the essential step in one of the major contemporary metal-catalyzed C-C coupling reactions. About 45 years ago, a Japanese and an American group almost simultaneously designed and executed palladium-mediated coupling reactions of aryl and alkenyl halides with alkenes [1]. In subsequent investigations, Richard Heck and his group developed this reaction into a catalytic transformation and started to demonstrate its usefulness as well as its rather broad scope. The real push to utilize this powerful C-C-bondforming process, however, started only around the mid-1980s, and by now, an impressive number of publications have established the meanwhile so-called Heck reaction [2] 1) as an indispensable method in Organic Synthesis [3][4][5][6][7]. The universal recognition of the importance of the Heck reaction and the Negishi as well as the Suzuki coupling eventually won the Nobel Prize for Richard Heck along with Ei-ichi Negishi and Akira Suzuki in 2010. The applications of the Heck reaction range from the preparation of -functionalized and unfunctionalized -hydrocarbons, novel polymers, and dyes to new advanced enantioselective syntheses of natural products and biologically active nonnatural compounds. The more or less simultaneous developments of mechanistically related variants, namely, the Kumada, Suzuki, Stille, Hiyama, and Negishi coupling reactions (Chapters 12, 2, 3, 4, and 15, respectively) of metallated alkenes and arenes with aryl and alkenyl halides or the metal-catalyzed formation and cycloisomerization of enynes have drawn profit from the improvement of and mechanistic insights into the Heck reaction. This, of course, applies vice versa as well. Using only a catalytic amount of a palladium(0) complex or a precursor to a palladium species, the Heck reaction can bring about unprecedented structural changes, particularly when conducted intramolecularly. The full potential of this palladium-catalyzed process is still being further explored as demonstrated by a total of over 7000 publications in the past 40 years by 1) The alkynylation of aryl and alkenyl halides, frequently also considered as Heck reactions, is described in Chapter 6.

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“…The active catalyst is actually believed to be nanodispersed palladium metal generated by reduction of the catalyst precursor by ethanol under basic conditions [150]. a Cross-coupling possible [2] The impact of silver(I) and thallium(I) salts [151] on Pd-catalyzed reactions extends beyond just increasing regioselectivities and enhancing reaction rates [152]. Without these additives, the arylation of allyl alcohols 27 afforded aldehydes and ketones 30, rather than the b-arylallyl alcohols 33.…”

Section: Effects Of Bases Ligands and Additivesmentioning

confidence: 99%

“…Cross-Coupling of Organyl Halides with Alkenes: the Heck ReactionScheme 5-7 Heck reaction with allyl alcohols in the absence and in the presence of silver salts[151,152].…”

mentioning

confidence: 99%

Cross‐Coupling of Organyl Halides with Alkenes: the Heck Reaction

Bräse

Meijere

2004

Metal‐Catalyzed Cross‐Coupling Reactions

View full text Add to dashboard Cite

The carbopalladation of an alkene by an organylpalladium halide is the essential step in one of the major contemporary metal-catalyzed C-C-coupling reactions. About 35 years ago, a Japanese and an American group almost simultaneously designed and executed palladium-mediated coupling reactions of aryl and alkenyl halides with alkenes [1]. In subsequent investigations, Richard Heck and his group developed this reaction into a catalytic transformation and started to demonstrate its usefulness as well as its rather broad scope. The real push to utilize this powerful C-C bond-forming process, however, started only around the mid-1980s, and by now an impressive number of publications has established the meanwhile socalled Heck reaction [2] as an indispensable method in organic synthesis [3]. The applications range from the preparation of hydrocarbons, novel polymers and dyes to new advanced enantioselective syntheses of natural products and biologically active non-natural compounds. The more or less simultaneous developments of mechanistically related variants, namely the Suzuki, Stille, Hiyama, Kumada and Negishi coupling reactions (see Chapters 2, 3, 4, 12 and 15 in this book, respectively) of metallated alkenes and arenes with aryl and alkenyl halides or the metal-catalyzed formation and cycloisomerization of enynes have drawn profit from the improvement of and mechanistic insights into the Heck reaction. This, of course, also applies vice versa. Using only a catalytic amount of a palladium(0) complex or a precursor to a palladium species, the Heck reaction can bring about unprecedented structural changes, particularly when conducted intramolecularly. The full potential of this palladium-catalyzed process is still being further explored, as demonstrated by a total of 2400 relevant publications during the past 10 years, and a continuous annual growth in publications of 15 % per year. Therefore, it is appropriate to say that the Heck reaction is one of the true "power tools" in contemporary organic synthesis [4], competing favorably with the Diels-Alder reaction (25 000 references), olefin metathesis (1500 references), Wittig reaction (15 000 references), or Claisen rearrangement (15 000 references). Scheme 5-1 Mechanism of the Heck reaction [7]. Pd(OTfa) 2 , P(2-furyl) 3 , iPr 2 EtN; Pd(OTfa) 2 or Pd(F 6 -acac) 2 ] and fluorinated phosphanes [90] [91]

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The effect of thallium (I) salts on palladium catalysed tandem cyclisation-anion capture processes.

Cited by 66 publications

References 14 publications

Intermolecular Heck Reaction: Scope, Mechanism, and Other Fundamental Aspects of the Intermolecular Heck Reaction

Intermolecular Heck Reaction: Scope, Mechanism, and Other Fundamental Aspects of the Intermolecular Heck Reaction

Cross‐Coupling of Organyl Halides with Alkenes – The Heck Reaction

Cross‐Coupling of Organyl Halides with Alkenes: the Heck Reaction

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