Recent Aspects of Transition Metal Catalyzed Reactions of Carbenes in the Realm of Biologically Active Substances

Demonceau, Albert; Noels, Alfred F.; Hubert, Aurélia

doi:10.1007/978-94-009-2867-1_4

Cited by 11 publications

(1 citation statement)

References 93 publications

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“…The next step is the addition of the diazo compound. Several possible modes of coordination of EDA to the Rh(I) center are conceivable. − Complexes where the diazo compound is coordinated to Rh via the carbon atom ( 5 ), the terminal diazo nitrogen ( 6 ), the carbonyl oxygen ( 7 ), or both nitrogen and oxygen ( 8 ) were computationally located (Figure ). It is complex 5 with the diazo compound coordinated via the carbon atom that is presumed to be the product-forming complex.…”

Section: Resultsmentioning

confidence: 99%

On the Mechanism of Cyclopropanation Reactions Catalyzed by a Rhodium(I) Catalyst Bearing a Chelating Imine-Functionalized NHC Ligand: A Computational Study

2011

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A computational study at the DFT level using BP86 and dispersion-corrected D-BP86 methods has been performed on the mechanism of a highly cis-diastereoselective cyclopropanation reaction between ethyl diazoacetate and styrene, catalyzed by a Rh(I) complex bearing a chelating imine-functionalized NHC ligand. The key steps in the mechanism have been elucidated. The favored mechanistic pathway was found to be a stepwise mechanism involving the formation of a Rh metallacyclobutane intermediate. The results from the theoretical study indicate that the diastereoselectivity is determined in the step where styrene coordinates to the Rh(I) carbenoid and that the high cis-diastereoselectivity can be attributed to an unfavorable steric interaction between styrene and the substituents on the N-aryl ring in the ligand system, which disfavors the formation of the trans cyclopropanation product.

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Section: Resultsmentioning

confidence: 99%

On the Mechanism of Cyclopropanation Reactions Catalyzed by a Rhodium(I) Catalyst Bearing a Chelating Imine-Functionalized NHC Ligand: A Computational Study

2011

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Intermolecular Metal‐Catalyzed Carbenoid Cyclopropanations

2001

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The metal‐catalyzed decomposition of diazo compounds in the presence of alkenes is a well‐established reaction. Since the original Organic Reactions review on the reaction of ethyl diazoacetate with alkenes and aromatic compounds in 1970, several new developments have revolutionized this area of chemistry. Most notably, major advances have been made in catalyst design such that highly chemoselective, diastereoselective and enantioselective carbenoid transformations can now be achieved. Furthermore, it has been recognized that a wide array of carbenoid structures can be utilized in this chemistry, leading to a broad range of synthetic applications. This chapter comprises coverage of the metal‐catalyzed intermolecular cyclopropanations of diazo compounds containing at least one adjacent electron‐withdrawing group. The coverage of diazoacetate chemistry will be limited to material since 1970 because the previous Organic Reactions review covers the earlier literature. The alkene component is limited to alkenes, dienes, furans, and pyrroles because these are the systems that have resulted in the greatest developments since the 1970 review. Metal‐carbenoid intermediates derived from diazo compounds undergo a variety of useful reactions, including cyclopropanation, insertion, and ylide formation. In recent years several excellent reviews have appeared on various aspects of this chemistry. Three recent reviews have focused on asymmetric intermolecular cyclopropanations. Several books and reviews on carbenoid chemistry have major sections on intermolecular cyclopropanations. Because of the historical central prominence of carbenoids derived from diazoacetates, most reviews have tended to focus on this class of carbenoids. In this chapter, a comparison is presented of the chemical differences that exist among the major classes of carbenoids that contain adjacent electron‐withdrawing groups. The extensive nature of the topic precludes coverage of related reactions such as the metal‐catalyzed decomposition of diazoalkanes, phenyldiazoalkanes, or vinyldiazoalkanes that lack adjacent electron‐withdrawing functionality. Other cyclopropanation reactions such as the Simmons‐Smith reaction, photochemical or thermal decomposition of diazo compounds in the presence of alkenes, and cyclopropanation using stoichiometric metal carbenes are not covered.

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Metal Catalysed Cyclopropanation

McKervey

2009

Patai's Chemistry of Functional Groups

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Introduction Cyclopropanation Using Diazoalkanes Cyclopropanation Using Diazocarbonyl Compounds Cyclopropanation Using Other Precursors Chemoselectivity in Metal Catalysed Cyclopropanation Regioselectivity in Metal Catalysed Cyclopropanation Stereochemical Features of Alkene Cyclopropanation Conclusion

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Recent Aspects of Transition Metal Catalyzed Reactions of Carbenes in the Realm of Biologically Active Substances

Cited by 11 publications

References 93 publications

On the Mechanism of Cyclopropanation Reactions Catalyzed by a Rhodium(I) Catalyst Bearing a Chelating Imine-Functionalized NHC Ligand: A Computational Study

On the Mechanism of Cyclopropanation Reactions Catalyzed by a Rhodium(I) Catalyst Bearing a Chelating Imine-Functionalized NHC Ligand: A Computational Study

Intermolecular Metal‐Catalyzed Carbenoid Cyclopropanations

Metal Catalysed Cyclopropanation

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