Allylic alkylation: nucleophilic attack on .pi.-allylpalladium complexes

Trost, Barry M.; Weber, Lothar; Strege, Paul E.; Fullerton, Terry J.; Dietsche, Thomas J.

doi:10.1021/ja00479a025

Cited by 141 publications

(38 citation statements)

References 14 publications

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“…2,3 Treatment of an olefin such as 2-ethylidenenopinane 1 , which was a mixture of geometric isomers, gave a single π-allylpalladium complex 2 (eq 1). 4 A broad range of di- and tri-substituted olefins reacted well. Most interestingly, the presence of a carbonyl group in the substrate did not interfere.…”

Section: Methodology Of Palladium Processesmentioning

confidence: 98%

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Metal catalyzed allylic alkylation: its development in the Trost laboratories

Trost

2015

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Section: Methodology Of Palladium Processesmentioning

confidence: 98%

“…2 The stereochemistry of the alkylation step was established to occur with inversion of configuration wherein the nucleophile attacked the π-allylpalladium species on the face opposite from where the palladium resided as shown in eq 1. 4 …”

Section: Methodology Of Palladium Processesmentioning

confidence: 99%

Metal catalyzed allylic alkylation: its development in the Trost laboratories

Trost

2015

Tetrahedron

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191

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“…A second regio-and diastereoselective palladium catalyzed reaction introduces a carbon side chain which ultimately could be converted by standard methods to both a carboxylic acid as well as a hydroxymethyl side chain. A major advantage of this approach is equivalently facile ac- 6 Vol. 50, No.…”

Section: Type B Enantiodiscriminationmentioning

confidence: 99%

“…1. Both the ionization 5) and nucleophilic addition 6) events involve bond cleavage and formation, respectively, that occur outside the coordination sphere of the metal and thus distal to the chiral ligands. Thus, chiral information must be transmitted from one face of the substrates to that on the side opposite to the metal.…”

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confidence: 99%

Pd Asymmetric Allylic Alkylation (AAA). A Powerful Synthetic Tool.

Trost

2002

Chem. Pharm. Bull.

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304

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Chiral compounds have many applications. None are more important than those related to biological targets. The chiral nature of biological receptors make chiral ligands common objectives as pharmaceuticals and agrichemicals. Thus, developing efficient synthetic methods to such compounds represents an important challenge. In spite of great advances, resolution methods still frequently represent the most economical method for commercial production in spite of the fact that the theoretical yield of the single desired enantiomer cannot exceed 50% unless the opposite enantiomer can be converted to the desired one. Using starting materials from the chiral pool also constitutes a common strategy. More recently, attention has shifted to inducing chirality into achiral precursors. Two tacts have been explored. In one, chiral auxiliaries, normally emanating from the chiral pool, are covalently attached to prochiral substrates.1) The advantage of this approach is the high degree of success in transmitting chiral information in this more controlled strategy. However, it suffers from numerous drawbacks. First, it requires stoichiometric amounts of the chiral auxiliary which ultimately is not part of the final product. It also requires additional steps to add and subsequently remove the chiral auxiliary. Clearly, the conceptually most attractive strategy is employing asymmetric catalytic reactions. 2)Some of these have achieved great success. Two of the most successful have been asymmetric catalytic hydrogenation and asymmetric catalytic oxidation of alkenes, notably epoxidation. These two reactions, in addition to virtually every other asymmetric catalytic reaction, share a common feature-the enantiodiscriminating event involves recognizing the enantiotopic faces of a prochiral p-unsaturation such as a carbonyl group or a double bond. Furthermore, each of these reactions also involve formation of just one bond type-a C-H bond in the case of hydrogenation and a C-O bond in the case of oxidation.Catalytic asymmetric allylic alkylation differs from virtually all other catalytic processes in two important ways. In the first, there are many enantiodiscriminating mechanisms, not just one. As shown in Fig. 1, there are at least five such mechanisms. As in most other catalytic asymmetric reactions, differentiating the enantiotopic faces of a p-unsaturation is one mechanism (Fig. 1, A). A second mechanism is differentiating enantiopic leaving groups (Fig. 1, B). Mechanism C involves differentiating enantiotopic termini of a pallylmetal intermediate. Since this intermediate derives from a chiral racemic precursor in which the chirality of the substrate is lost, this deracemization constitutes a dynamic kinetic asymmetric transformation (DYKAT). Mechanism D is a varient of mechanism A wherein the p-allylmetal intermediates interconvert faster than they are attacked by a nucleophile and asymmetric induction derives from differential rates of reaction of the two diastereomeric intermediates. This mechanism allows employment of either an ...

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“…The regiochemistry of attack in allylic substitution varies greatly with respect to the metal, ligands, nucleophile, and allyl substituent type. For example, if there is an electron-accepting substituent (R) on the allyl group, then attack at the more substituted position is preferred (8)(9)(10). In contrast, if R is an electron-donating group, attack at the less substituted position is more favoured (11)(12)(13)(14)(15).…”

Section: Introductionmentioning

confidence: 99%

A DFT investigation into the origin of regioselectivity in palladium-catalyzed allylic amination

Iuliis¹,

Watson²,

Yudin³

et al. 2009

Can. J. Chem.

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The addition of amines or aziridines to prenylacetate is catalyzed by palladium phosphine complexes. The first-formed products have recently been shown to be the branched olefins R 2 NCMe 2 CH=CH 2 , R = alkyl, or R 2 = 1,2-C 6 H 10 , for example. DFT calculations using the MPW1K functional were performed on reactions of the suspected intermediate η 3 -prenyl complex [Pd(η 3 -Me 2 CCHCH 2 )(PH 3 ) 2 ] + with dimethylamine and ethylene imine. The activation barrier for the nucleophilic attack by the amine or the aziridine is calculated to be similar for either the sterically hindered site of the π-allyl ligand to produce the branched olefin complex or the unhindered site to give the linear olefin complex. Therefore, these calculations do not reveal the experimentally observed preference for attack. This observation, along with the experimental observation of lack of isomerization of the branched olefin product of the aziridine reactions, appears to rule out the intermediacy of a π-allyl complex [Pd(η 3 -Me 2 CCHCH 2 )L 2 ] + , L = phosphine or L 2 = diphosphine in the C-N bond-forming reaction.Résumé : L'addition d'amines ou d'aziridines à l'acétate de prényle est catalysée par les complexes des phosphines de palladium. Il a été démontré récemment que les premiers produits formés sont des oléfines ramifiées, telles les R 2 NCMe 2 CH=CH 2 dans lesquelles R = alkyle ou R 2 = 1,2-C 6 H 10 . On a effectué des calculs théoriques de la fonctionnelle de densité à l'aide d'une fonction MW1K sur les réactions de l'intermédiaire prévu, le complexe η 3 -prényle [Pd(η 3 -Me 2 CCHCH 2 )(PH 3 ) 3 ] + avec la diméthylamine et l'éthylèneimine. On a calculé que la barrière d'activation à l'attaque nucléophile par l'amide ou l'aziridine est semblable que ce soit pour le site stériquement empêché du ligand π-allyle à produire la complexe à oléfine ramifiée ou le site non empêché à donner le complexe de l'oléfine linéaire. Ces calculs ne permettent donc pas de confirmer la préférence observée expérimentalement pour cette attaque. Cette observation ainsi que l'observation expérimentale que l'oléfine ramifiée des réactions de l'aziridine ne conduit pas à une isomérisation semble éliminer la possibilité que le complexe π-allyle [Pd(η 3 -Me 2 CCHCH 2 )L 2 ] + , L = phosphine ou L 2 = diphosphine, soit un intermédiaire dans la réaction de formation de la liaison C-N.Mots-clés : allylpalladium, amine, aziridine, calculs théoriques de la fonctionnelle de densité, mécanisme, catalyse.[Traduit par la Rédaction] Zimmer De Iuliis et al. 62

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Allylic alkylation: nucleophilic attack on .pi.-allylpalladium complexes

Cited by 141 publications

References 14 publications

Metal catalyzed allylic alkylation: its development in the Trost laboratories

Metal catalyzed allylic alkylation: its development in the Trost laboratories

Pd Asymmetric Allylic Alkylation (AAA). A Powerful Synthetic Tool.

A DFT investigation into the origin of regioselectivity in palladium-catalyzed allylic amination

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