Rhodium(II)‐Catalyzed 1,3‐Dipolar Cycloaddition Reactions

Savizky, Ruben M.; Austin, David

doi:10.1002/3527604693.ch19

Cited by 11 publications

(6 citation statements)

References 132 publications

(167 reference statements)

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“…Three-component cycloadditions, such as the Pauson-Khand reaction ([2+2+1])4 and the alkyne cyclotrimerization ([2+2+2])5, are also common examples. The formation of heterocycles by these processes is less well developed, with aziridinations6 and 1,3-dipolar cycloadditions7 being prominent exceptions 8. Given the demonstrated importance of nitrogen heterocycles in biology and medicine, the stereoselective synthesis of these moieties constitutes an area of intense research.…”

Section: Introductionmentioning

confidence: 99%

Multi-component cycloaddition approaches in the catalytic asymmetric synthesis of alkaloid targets

2009

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Cycloaddition reactions are attractive strategies for rapid formation of molecular complexity in organic synthesis as multiple bonds are formed in a single process. To this end, several research groups have been actively involved in the development of catalytic methods to activate readily accessible π-components to achieve cycloadditions. However, the use of C-N π-components for the formation of heterocycles by these processes is less well developed. It has been previously demonstrated that the combination of different isocyanates with two alkynes yields pyridones of several types by metal-catalyzed [2+2+2] cycloadditions. The potential of this chemistry has been extended to alkenes as C-C π-components, allowing the formation of sp 3 -stereocenters. In this tutorial review directed towards [n+2+2] cycloaddition of heterocumulenes, alkynes and alkenes, the recent advances in catalytic asymmetric synthesis of indolizidine, quinolizidine and azocine skeletons are discussed.

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Section: Introductionmentioning

confidence: 99%

Multi-component cycloaddition approaches in the catalytic asymmetric synthesis of alkaloid targets

2009

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“…We attribute the product of the rhodium-catalyzed reaction of 10a to rapid formation of an ylide following carbene formation (Figure ). Ylide formation is well-known in dirhodium carbene chemistry, and the enforced propinquity of the ester carbonyl likely encourages this mode of reactivity. − Following ylide formation, the alcohol traps the oxocarbenium as the orthoester, and the dirhodium enolate is protonated to restore the catalyst. , Whether the observed single diastereoisomer is the result of a rapid epimerization and high thermodynamic preference, or a kinetically controlled intramolecular protonation step, is unclear. Conversely, protonation of the dirhodium enolate could occur first, and the resulting oxocarbenium/alkoxide ion pair could collapse in a facially selective manner to afford the single diastereoisomer.…”

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confidence: 99%

Donor–Acceptor–Acceptor 1,3-Bisdiazo Compounds: An Exploration of Synthesis and Stepwise Reactivity

2020

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Metal carbenes, derived from the decomposition of diazo compounds, are valued for their capacity to perform a variety of transformations. A unique class of acyclic, bis-diazo compounds, the donor–acceptor–acceptor 1,3-bisdiazo compounds, are described herein. These compounds are available from acyclic β-keto esters and especially reactive at the donor–acceptor diazo unit. These bisdiazo compounds react smoothly with rhodium acetate and alcohols to give monodiazo, cyclic orthoesters, presumably through the capture of a transient oxonium ylide.

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“…Over the past three decades, since the seminal work of Bien et al, rhodium(II) catalyzed carbonyl ylide formation and subsequent dipolar cycloadditions have been extensively studied and broadly utilized. The ligand induced chemoselectivity of these reactions − as well as asymmetric induction induced by chiral Rh(II) catalysts − have also been the subjects of several studies and inspired the use of these reactions as key steps in syntheses of numerous natural products, − including our own racemic synthesis of epoxysorbicillinol …”

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confidence: 99%

“…Although rhodium initiated carbonyl ylide formation is driven by the electrophilic nature of the incipient rhodium carbenoid, , examples wherein this electrophilicity has been exploited in clearly differentiating between two equidistant carbonyls are unknown . However, in an example taken from the extensive studies of Padwa in this area (Scheme ) one might glean some evidence of such selectivity .…”

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Chemoselective Intramolecular Carbonyl Ylide Formation through Electronically Differentiated Malonate Diesters

2015

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A method for chemoselective carbonyl ylide formation utilizing the Rh(II) catalyzed decomposition of electronically differentiated diazo malonates is disclosed. Treatment of ethyl, trifluoro ethyl diazo malonate with a Rh(II) catalyst selectively forms a carbonyl ylide from the relatively electron rich ethyl ester. This carbonyl ylide can be trapped by various alkynes giving highly functionalized oxabicyclic compounds in a chemo-, regio-, and diastereoselective fashion.

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Rhodium(II)‐Catalyzed 1,3‐Dipolar Cycloaddition Reactions

Cited by 11 publications

References 132 publications

Multi-component cycloaddition approaches in the catalytic asymmetric synthesis of alkaloid targets

Multi-component cycloaddition approaches in the catalytic asymmetric synthesis of alkaloid targets

Donor–Acceptor–Acceptor 1,3-Bisdiazo Compounds: An Exploration of Synthesis and Stepwise Reactivity

Chemoselective Intramolecular Carbonyl Ylide Formation through Electronically Differentiated Malonate Diesters

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