Isoerization of allylic acetates catalyzed by palladium. New method for stereocontrol.

Trost, Barry M.; Verhoeven, Thomas B.; Fortunak, Joseph; McElvain, S. M.

doi:10.1016/s0040-4039(01)93957-7

Cited by 134 publications

(44 citation statements)

References 9 publications

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“…These results concerning the reversibility of the oxidative addition, that is, the existence of the backward reaction in Equation (15), are in agreement with work done by Trost and Bäckvall [7,8] as recalled in the Introduction. Our work establishes this reversibility kinetically and determines the thermodynamics of the equilibrium.…”

Section: Resultssupporting

confidence: 92%

“…[7] Such racemization might be responsible for the loss of stereospecificity observed in some palladiumcatalyzed allylic substitutions. [8] This suggests that both of the reactions in Equations (2) and (3) are reversible and that the acetate ion is able to attack the intermediate cationic pallylpalladium complex, resulting in the inversion of the initial configuration of the chiral allylic acetate.…”

Section: (Or Bphmentioning

confidence: 99%

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Evidence of the Reversible Formation of Cationic π-Allylpalladium(II) Complexes in the Oxidative Addition of Allylic Acetates to Palladium(0) Complexes

et al. 1999

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It has been established that the oxidative addition of allylic acetate with the palladium(0) complex, generated from a mixture of Pd(dba) 2 2 PPh 3 , affords a cationic p-allylpalladium(ii) complex. This reaction is reversible and proceeds through at least two successive equilibria. The overall equilibrium constant has been determined in THF and DMF. The acetate ion does not act as a simple leaving group, but plays the role of a nucleophile able to react with cationic p-allylpalladium(ii) complexes to reproduce the allylic acetate; a process that may be responsible for the racemization of chiral allylic acetates. In DMF, no significant ion pairing occurs and free ions are formed. On the other hand, in THF almost complete ion pairing occurs and almost no free ions are produced.

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Section: Resultssupporting

confidence: 92%

Section: (Or Bphmentioning

confidence: 99%

Evidence of the Reversible Formation of Cationic π-Allylpalladium(II) Complexes in the Oxidative Addition of Allylic Acetates to Palladium(0) Complexes

et al. 1999

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“…[1] More recently, however, this reaction has been found to be an essential step in the catalytic cycles of Hecktype reactions, [2] isomerizations of alkynes to dienes, [3] cyclizations of enynes, [4] and alkene methyl acrylate polymerizations. [5] As shown by the fundamental work of Trost [6] and Tsuji, [7] smooth access to 1,3-dienes is opened when allylic acetates are submitted to palladium-catalyzed eliminations. Allylic carbonates were found to undergo this reaction under even milder conditions [8] and Pd(OAc) 2 /P(nBu) 3 turned out to be the catalyst of choice in this case.…”

Section: Introductionmentioning

confidence: 99%

“…Thus, H a X is liberated under the formation of 4 b. [6,7] On the other hand, a base-induced abstraction of the b-hydrogen in 3 a has been postulated to account for the anti elimination of allyl palladium complexes. [13,14] Thus the base B À attacks the hydrogen atom H a , which is in an anti orientation relative to the palladium in the complex 3 a.…”

Section: Introductionmentioning

confidence: 99%

Evidence for Competing syn and anti Pathways in Palladium-Catalyzed Eliminations of Acyclic Allylic Carbonates

Schwarz

Braun

1999

Chemistry - A European Journal

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Syn-and anti-configured carbonates 6 a and 6 b, available from stereoselective aldol additions and subsequent protection with methyl chloroformate, serve as probes for the elucidation of the stereochemistry of the b-PdÀH elimination. Upon treatment with [Pd(PPh 3 ) 4 ], the carbonates 6 a and 6 b give the dienes 7 a and 7 b in different ratios; the latter stereoisomer 7 b is formed as a result of p ± s ± p conversions. Both syn and anti eliminations are shown to occur as competing reactions, the former one being the strongly preferred pathway. The highly reactive [Pd{P(nBu) 3 } 4 ] catalyst, generated in situ from Pd(OAc) 2 and P(nBu) 3 causes thermodynamic control in the elimination; thus, it serves as a smooth reagent for Z ± E isomerization.

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“…[1][2][3][4] Moreover, some of them (sulfonal, trional, and tetronal) are classical sedative-hypnotics 5) ( Fig. 1).…”

mentioning

confidence: 99%

Niobium(V) Chloride Catalyzed Oxidation of Dithioacetals with 30% Hydrogen Peroxide: A Concise Preparation of Bissulfonylmethylene Compounds

Kirihara

Goto

Noguchi

et al. 2013

CHEMICAL & PHARMACEUTICAL BULLETIN

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Isoerization of allylic acetates catalyzed by palladium. New method for stereocontrol.

Cited by 134 publications

References 9 publications

Evidence of the Reversible Formation of Cationic π-Allylpalladium(II) Complexes in the Oxidative Addition of Allylic Acetates to Palladium(0) Complexes

Evidence of the Reversible Formation of Cationic π-Allylpalladium(II) Complexes in the Oxidative Addition of Allylic Acetates to Palladium(0) Complexes

Evidence for Competing syn and anti Pathways in Palladium-Catalyzed Eliminations of Acyclic Allylic Carbonates

Niobium(V) Chloride Catalyzed Oxidation of Dithioacetals with 30% Hydrogen Peroxide: A Concise Preparation of Bissulfonylmethylene Compounds

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