Anti-stereoselectivity in the palladium(0)-catalyzed conversion of propargylic esters into allenes by phenylzinc chloride

Elsevier, Cornelis J.; Stehouwer, Petra M.; Westmijze, H.; Vermeer, P.

doi:10.1021/jo00155a036

Cited by 116 publications

(31 citation statements)

References 4 publications

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“…The reaction of 3 with acetic anhydride at room temperature in the presence of 4‐( N , N ‐dimethylamino)pyridine (DMAP) provided propargyl acetate 4 25. Enyne‐allene EA1 was finally obtained by the Pd‐promoted reaction of p ‐AnZnCl with 4 at –60 °C 26. The 1 H, 13 C, and 19 F NMR, IR, and HRMS data convincingly supported the structural assignment of EA1 .…”

Section: Resultsmentioning

confidence: 63%

Fluoro‐Ene Reaction Versus [2+2] Cycloaddition in the Thermal C²–C⁶ Cyclization of Enyne‐Allenes: An Experimental and Theoretical Investigation

et al. 2014

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A series of fluoroalkyl‐substituted enyne‐allenes have been synthesized by a new route with the aim of elucidating the possibility of a fluoro‐ene reaction via an intermediate fulvenyl diradical generated in the thermal C2–C6 (Schmittel) cyclization reaction. As a result of the strong C–F bond, fluorine atom transfer was not observed. Instead, 1H‐cyclobuta[a]indenes were formed in good yields despite the high strain energy. DFT calculations at the B3LYP level of theory indicated that although the fluoro‐ene reaction is the most exothermic reaction available, cyclobutene formation is kinetically favored over the [1,5]‐fluorine shift by 5–15 kcal mol–1 in various model compounds.

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Section: Resultsmentioning

confidence: 63%

Fluoro‐Ene Reaction Versus [2+2] Cycloaddition in the Thermal C²–C⁶ Cyclization of Enyne‐Allenes: An Experimental and Theoretical Investigation

et al. 2014

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“…Thus, authentic (R)-allene 12 was synthesized from (R)-15. In corroboration of the assignment, enantiomerically enriched (R)-allene 12 was prepared via a different authentic route from (S)-4 with a Pd catalyst [17]. Comparison of the directions of optical rotation established the absolute configuration of the allene 12 obtained from enantiomerically enriched (S)-4.…”

mentioning

confidence: 86%

A Study of the Stereochemical Course of β‐Oxygen Elimination with a Rhodium(I) Complex

Murakami

Igawa

2002

Helvetica Chimica Acta

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Dedicated to Professor Dieter Seebach on the occasion of his 65th birthdayThe stereochemical course of b-oxygen elimination of an organorhodium(I) complex was investigated through the Rh-catalyzed addition of phenylboronic acid to a chiral propargyl acetate to produce an allene. The degree of chirality transfer suggests that the b-oxygen elimination takes place in both syn and anti modes.Introduction. ± Transition metal catalyzed organic transformations constitute an important class of synthetic tools. b-Elimination is often involved in these processes. For example, b-H elimination is a crucial step in the Pd-catalyzed Mizoroki-Heck reaction. b-H Elimination is known to proceed in a syn mode with a variety of transition metals [1]. On the other hand, little is known about the stereochemical course of b-O elimination, although this is also a common process [2]. Hacksell and Daves found that b-OH elimination took place via a syn mode [3] and b-AcO elimination via an anti mode [4]. Zhu and Lu, on the other hand, found only anti eliminations for b-Cl, b-AcO, and b-OH groups in Pd-catalyzed ene-yne cyclization reactions [5]. This paper provides experimental results that suggest that the b-AcO elimination of an organorhodium(I) complex takes place via both syn and anti modes.

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“…Although the absolute configurations of the above-obtained chiral allenes were not established conclusively, the origin of the anti-substitution products (S)-2a and (S)-2i is conceivable by assuming the reaction sequence depicted in Scheme 3 11 . Thus, the oxidative insertion of the Pd(0) catalyst into mesylate 1 gives rise to the allenylpalladium intermediate 6 (inversion), which is in turn transformed into 7 (retention) via nucleophilic displacement of the mesylate ligand by the organozinc reagent.…”

Section: Mechanism For the Formation Of Allenesmentioning

confidence: 98%

Fluorine-Containing Allenylpalladium Complexes. Synthesis of Optically Active Fluoroalkylated Allenes and Furan Derivatives

Konno

Tanikawa

Ishihara

et al. 2002

Collect. Czech. Chem. Commun.

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The reaction of fluoroalkylated propargyl mesylates with various nucleophiles, such as zinc reagents and enolates derived from 1,3-dicarbonyl compounds, in the presence of a palladium catalyst was investigated in detail. Various zinc reagents participated in the coupling reaction to give the corresponding fluoroalkylated allenes in good yields. When chiral mesylates were employed, the corresponding optically active allenes were obtained without any loss of enantiomeric purity in the reaction. On the other hand, treatment of trifluoromethylated propargyl mesylate with stabilized carbanions derived from methyl acetoacetate, acetylacetone, and diethyl malonate afforded fluorine-containing furan derivatives in moderate to high yields.Transition metals are able to catalyze a wide range of synthetically useful organic reactions, very often with high levels of chemo-and stereoselectivity 1 . In particular, palladium-catalyzed reactions have been employed with success in a number of important chemical processes, such as Stille coupling 2 , Suzuki coupling 3 , Negishi coupling 4 , Heck reactions 5 , and allylic substitution 6 .Palladium-catalyzed reactions of propargylic compounds have also been investigated in considerable detail over the last twenty years, and are considered as some of the most valuable synthetic reactions 7 . In sharp contrast to these investigations, palladium-catalyzed transformations of fluorine-

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Anti-stereoselectivity in the palladium(0)-catalyzed conversion of propargylic esters into allenes by phenylzinc chloride

Abstract: 16) For recent reviews of lanthanide shift reagents see: (a) Hofer, O.

Cited by 116 publications

References 4 publications

Fluoro‐Ene Reaction Versus [2+2] Cycloaddition in the Thermal C²–C⁶ Cyclization of Enyne‐Allenes: An Experimental and Theoretical Investigation

Fluoro‐Ene Reaction Versus [2+2] Cycloaddition in the Thermal C²–C⁶ Cyclization of Enyne‐Allenes: An Experimental and Theoretical Investigation

A Study of the Stereochemical Course of β‐Oxygen Elimination with a Rhodium(I) Complex

Fluorine-Containing Allenylpalladium Complexes. Synthesis of Optically Active Fluoroalkylated Allenes and Furan Derivatives

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Anti-stereoselectivity in the palladium(0)-catalyzed conversion of propargylic esters into allenes by phenylzinc chloride

Abstract: 16) For recent reviews of lanthanide shift reagents see: (a) Hofer, O.

Cited by 116 publications

References 4 publications

Fluoro‐Ene Reaction Versus [2+2] Cycloaddition in the Thermal C2–C6 Cyclization of Enyne‐Allenes: An Experimental and Theoretical Investigation

Fluoro‐Ene Reaction Versus [2+2] Cycloaddition in the Thermal C2–C6 Cyclization of Enyne‐Allenes: An Experimental and Theoretical Investigation

A Study of the Stereochemical Course of β‐Oxygen Elimination with a Rhodium(I) Complex

Fluorine-Containing Allenylpalladium Complexes. Synthesis of Optically Active Fluoroalkylated Allenes and Furan Derivatives

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Fluoro‐Ene Reaction Versus [2+2] Cycloaddition in the Thermal C²–C⁶ Cyclization of Enyne‐Allenes: An Experimental and Theoretical Investigation

Fluoro‐Ene Reaction Versus [2+2] Cycloaddition in the Thermal C²–C⁶ Cyclization of Enyne‐Allenes: An Experimental and Theoretical Investigation