Reorganization of Enynes Catalyzed by Platinum Salts

Añorbe, Loreto; Domı́nguez, Gema; Pérez‐Castells, Javier

doi:10.1002/chem.200400089

Cited by 86 publications

(24 citation statements)

References 26 publications

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“…Stoichiometric examples of platinummediated olefin activation have been recently reviewed, [3] and only selected examples are discussed here. Related chemistry based on the platinum-catalyzed activation of alkynes, such as enyne cycloisomerization, [4][5][6] is not covered. Addition reactions that are commonly believed to proceed by a 1,2-migratory insertion of the olefin into a platinum-element bond, such as hydrogenation and hydrosilylation, [7] are also not covered.…”

Section: Introductionmentioning

confidence: 99%

Electrophilic Activation of Alkenes by Platinum(II): So Much More Than a Slow Version of Palladium(II)

2007

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The electrophilic activation of alkenes by transition-metal catalysts is a fundamental step in a rapidly growing number of catalytic processes. Although palladium is the best known metal for this purpose, the special properties of its third-row cousin platinum (strong metal-ligand bonds and slow substitution kinetics) have enabled the development of transformations that are initiated by addition to the C=C bonds by protic carbon, nitrogen, oxygen, and phosphorus nucleophiles, as well as alkene or arene nucleophiles. Additionally, reactivity profiles, which are often unique to platinum, provide wholly new reaction products. This Review concerns platinum-catalyzed electrophilic alkene activation reactions, with a special emphasis on the mechanistic properties of known systems, on the differences between platinum and palladium catalysts, and on the prospects for the development of new systems.

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Section: Introductionmentioning

confidence: 99%

Electrophilic Activation of Alkenes by Platinum(II): So Much More Than a Slow Version of Palladium(II)

2007

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“…[2] Among available atom-economic transformations, [3] the cycloisomerization of enynes remains unique because of the increased molecular complexity achieved in one chemical step. [4] After extensive studies with palladium [5] and platinum, [6] gold(I) and goldA C H T U N G T R E N N U N G (III) salts have emerged lately as powerful catalysts for a myriad of transformations involving enynes. [7,8] In this context, enyne derivatives with an ester group at the propargylic position can be regarded as a special class of substrates due to their atypical reactivity pattern.…”

mentioning

confidence: 99%

Gold‐ and Platinum‐Catalyzed Cycloisomerization of Enynyl Esters versus Allenenyl Esters: An Experimental and Theoretical Study

Marion

Lemière

Correa

et al. 2009

Chemistry A European J

129

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Ester-way to heaven: Unexpected formation of bicyclo[3.1.0]hexene 4 was the main focus of combined experimental and theoretical studies on the Au-catalyzed cycloisomerization of branched dienyne 1 (see scheme), which provided better understanding of the mechanistic details governing the cyclization of enynes bearing a propargylic ester group.Experimental and theoretical studies on Au- and Pt-catalyzed cycloisomerization of a branched dienyne with an acetate group at the propargylic position are presented. The peculiar architecture of the dienyne precursor, which has both a 1,6- and a 1,5-enyne skeleton, leads, in the presence of alkynophilic gold catalysts, to mixtures of bicyclic compounds 3, 4, and 5. Formation of unprecedented bicyclo[3.1.0]hexene 5 is the main focus of this study. The effect of the ancillary ligand on the gold center was examined and found to be crucial for formation of 5. Further mechanistic studies, involving cyclization of an enantioenriched dienyne precursor, (18)O-labeling experiments, and DFT calculations, allowed an unprecedented reaction pathway to be proposed. We show that bicyclo[3.1.0]hexene 5 is likely formed by a 1,3-OAc shift/allene-ene cyclization/1,2-OAc shift sequence, as calculated by DFT and supported by Au-catalyzed cyclization of isolated allenenyl acetate 7, which leads to improved selectivity in the formation of 5. Additionally, the possibility of OAc migration from allenyl acetates was supported by a trapping experiment with styrene that afforded the corresponding cyclopropane derivative. This unprecedented generation of a vinyl metal carbene from an allenyl ester supports a facile enynyl ester/allenenyl ester equilibrium. Further examination of the difference in reactivity between enynyl acetates and their corresponding [3,3]-rearranged allenenyl acetates toward Au- and Pt-catalyzed cycloisomerization is also presented.

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“…Excellent reviews have been compiled highlighting different aspects of the advances in these cyclization reactions (11,363,(401)(402)(403)(404)(405)(406)(407)(408). By definition, enyne metathesis is a bond reorganization of an alkene and an alkyne to produce a 1,3-diene (403, 406 ,407) (Scheme 39).…”

Section: B Intramolecular Ring-closing Enyne Metathesismentioning

confidence: 99%

“…The synthetic value of this reaction is enhanced by the fact that, in addition to being a means to an end in itself, the 1,3-diene systems thus formed are themselves versatile synthetic reagents that can undergo further selective transformations (e.g., cycloaddition reactions). The metathesis reaction can be catalyzed by metal carbenes or by low-valent transition metals (e.g., chromium, ruthenium, iridium, palladium, platinum, gold, and their salt complexes) (401,(410)(411)(412)(413)(414)(415)(416)(417)(418)(419)(420). Synthetic applications of enyne metathesis can be separated into three main areas: intramolecular (ring-closing) enyne metathesis; intermolecular (cross) enyne metathesis, and tandem enyne metathesis.…”

Section: B Intramolecular Ring-closing Enyne Metathesismentioning

confidence: 99%

Unique Metal‐Diyne, ‐Enyne, and ‐Enediyne Complexes: Part of the Remarkably Diverse World of Metal‐Alkyne Chemistry

Bhattacharyya

Sangita

Zaleski

2007

Progress in Inorganic Chemistry

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Reorganization of Enynes Catalyzed by Platinum Salts

Cited by 86 publications

References 26 publications

Electrophilic Activation of Alkenes by Platinum(II): So Much More Than a Slow Version of Palladium(II)

Electrophilic Activation of Alkenes by Platinum(II): So Much More Than a Slow Version of Palladium(II)

Gold‐ and Platinum‐Catalyzed Cycloisomerization of Enynyl Esters versus Allenenyl Esters: An Experimental and Theoretical Study

Unique Metal‐Diyne, ‐Enyne, and ‐Enediyne Complexes: Part of the Remarkably Diverse World of Metal‐Alkyne Chemistry

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