Metal‐catalyzed carbenoid reactions with iodonium and sulfonium ylides

Müller, Paul; Fernández, Daniel; Nury, Patrice; Rossier, Jean-Claude

doi:10.1002/(sici)1099-1395(199805)11:5<321::aid-poc6>3.0.co;2-#

Cited by 60 publications

(7 citation statements)

References 82 publications

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“…Mn(III) -, Fe(III) -, or Rh(II) -catalyzed intra -and intermolecular C -H insertions has been achieved with tosylimidophenyliodinane 184 [251] . Effective intermolecular C -H amination was later demonstrated by Muller and others using p -nitrophenylsulfonyl imidoiodinane 185 [71,75,77] . This class remains the most widely used among nitrene precursors.…”

Section: Generation Of Metal Nitrenoids and Their Reactionsmentioning

confidence: 99%

Asymmetric Synthesis through C–H Activation

Davies

Hansen

2010

Catalytic Asymmetric Synthesis

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Section: Generation Of Metal Nitrenoids and Their Reactionsmentioning

confidence: 99%

Asymmetric Synthesis through C–H Activation

Davies

Hansen

2010

Catalytic Asymmetric Synthesis

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“…The reader is also encouraged to read a previous interesting review on the theme that includes the chemistry of iodonium and sulfonium ylides. [21]…”

Section: Introductionmentioning

confidence: 99%

Sulfoxonium and Sulfonium Ylides as Diazocarbonyl Equivalents in Metal‐Catalyzed Insertion Reactions

2013

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Since the pioneering contribution of Corey and Chaykovsky in 1965, sulfoxonium and sulfonium ylides have proven to be versatile intermediates in organic synthesis. One of their important applications, though not yet throughly investigated, is their substitution of diazocarbonyl compounds as safer carbene precursors. This microreview provides an overview and recent applications of sulfoxonium and sulfonium ylides in inter‐ and intramolecular metal‐catalyzed insertion reactions. It also plans to illustrate the promising synthetic utility of these stable carbene precursors in industry, mitigating potential safety problems generally encountered when the equivalent diazo compounds are employed. Moreover, it aims to inspire new contributions to this exciting growing area, especially in catalytic asymmetric reactions.

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“…Both precursors afforded the same selectivities in the intermolecular cyclopropanation of substituted styrenes and in the intramolecular competition for cyclopropanation vs. CH insertion. In addition, identical enantioselectivities resulted when the intramolecular CH insertion of a diazoacetoacetate and the corresponding phenyliodonium ylide was carried out in the presence of Ikegamis chiral [Rh II (carboxylato)] catalyst [6]. These results are consistent with a carbenoid mechanism.…”

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confidence: 99%

“…Unfortunately, the lack of reactivity of diazo compound 14a does not allow comparison with the enantioselectivities achieved with the ylides, and it is not clear whether the less than 100% enantioselectivity must be attributed to an inadequate choice of catalysts or to competing, unselective cyclopropanation pathways. Although we have not observed spontaneous cyclopropanations of ylides in the absence of catalysts in the present investigation, such reactions have been reported in the past not only by Moriarty et al [7], but also by ourselves [6], and for these reactions the mechanism outlined in Scheme 1, or a radical version thereof, is plausible. The present results lend some support for a metal carbenoid intermediate in the main pathway of the Cu-catalyzed ylide decomposition.…”

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confidence: 99%

Carbenoid Pathways in Copper-Catalyzed Intramolecular Cyclopropanations of Phenyliodonium Ylides

Müller¹,

Boléa²

2001

HCA

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The enantioselectivity of the copper-catalyzed intramolecular cyclopropanation of allyl diazomalonates and the corresponding phenyliodonium ylides was investigated with a series of chiral, non-racemic ligands. The reaction of 6b in the presence of the bis [dihydrooxazole] ligand Xa in refluxing 1,2-dichloroethane proceeded to 8b with an enantiomer excess (ee) of up to 72% under optimized conditions. In contrast, 8b resulting from reaction of ylide 7b with the same ligand, but in CH 2 Cl 2 at 08, had an ee of only 30%. With other ligands, diazomalonate 6b reacted with a lower enantioselectivity than ylide 7b, however. The intramolecular cyclopropanation of the acetoacetate-derived phenyliodonium ylide 15b afforded 16b with 68% ee with ligand Xa, but the corresponding diazo compound was unreactive when exposed to chiral copper catalysts. The observation of asymmetric induction in the Cu-catalyzed reactions of the ylides 7 and 15 is consistent with a carbenoid mechanism; however, the discrepancy of the enantioselectivities observed between diazomalonate 6b and ylide 7b suggests a competing unselective pathway for cyclopropanation outside of the coordination sphere of copper.[4] decomposition of phenyliodonium ylides [5] affords products typical for carbene or metal carbenoid intermediates. The mechanism of these reactions is, however, controversial. Carbene or carbenoid pathways have often been proposed or assumed, but experimental evidence in support of these hypotheses is scarce. Some years ago, we have investigated the decomposition of some diazo compounds and the corresponding phenyliodonium ylides in the presence of [Rh II (carboxylato)] catalysts. Both precursors afforded the same selectivities in the intermolecular cyclopropanation of substituted styrenes and in the intramolecular competition for cyclopropanation vs. CH insertion. In addition, identical enantioselectivities resulted when the intramolecular CH insertion of a diazoacetoacetate and the corresponding phenyliodonium ylide was carried out in the presence of Ikegamis chiral [Rh II (carboxylato)] catalyst [6]. These results are consistent with a carbenoid mechanism.However, the majority of the synthetically useful reactions with phenyliodonium ylides have been carried out under Cu-catalysis, and for Cu-catalysts the mechanism is not established. Moriarty et al. investigated the intramolecular cyclopropanation of ylide 1 to the tricyclic ketone 4 in the presence of [CuCl] (Scheme 1) [7]: the reaction proceeded in yields of 76 to 90%; surprisingly, it also occurred in the absence of catalyst, albeit in lower yield. The authors proposed a mechanism in which the electrophilic iodonium center attacks the CC bond to afford a carbenium ion 2, which, subsequently, undergoes transannular alkylation to yield 3. Reductive elimination of PhI from 3 finally produces the cyclopropane 4. The catalytic effect of Cu I , in turn, was ascribed to electron transfer. A carbene mechanism was specifically ruled out.

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Metal‐catalyzed carbenoid reactions with iodonium and sulfonium ylides

Cited by 60 publications

References 82 publications

Asymmetric Synthesis through C–H Activation

Asymmetric Synthesis through C–H Activation

Sulfoxonium and Sulfonium Ylides as Diazocarbonyl Equivalents in Metal‐Catalyzed Insertion Reactions

Carbenoid Pathways in Copper-Catalyzed Intramolecular Cyclopropanations of Phenyliodonium Ylides

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