Some New Nazarov Chemistry

Tius, Marcus A.

doi:10.1002/ejoc.200500005

Cited by 344 publications

(78 citation statements)

References 69 publications

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“…In particular, the energy profiles of the "conventional" Nazarov reaction [Eqs. (5) and (6)] are shown in Figure 1A and B, while the profiles of Equations (7) and (8), in which an alkyl group replaces the hydrogen atom on the oxygen of the pentadienyl cation, are reported in Figure 1C and D.…”

Section: Resultsmentioning

confidence: 97%

“…[3][4][5][6][7]25] The potential of the Nazarov reaction in organic synthesis has grown enormously in the past few years as a consequence of a series of studies on the electrocyclization reactions of cyclic systems. Namely, systems in which one of the double bonds participating in the cyclization process is embedded in either a carbocycle or a heterocycle (O-heterocycle derivatives being predominant) [Eqs. (1)- (4)].…”

Section: Introductionmentioning

confidence: 99%

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Density Functional Studies on the Nazarov Reaction Involving Cyclic Systems

Cavalli

Masetti

Recanatini

et al. 2006

Chemistry A European J

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Density functional theory (DFT) has been used to define the energy profiles of the Nazarov reaction involving cyclic systems. The calculations were carried out at the B3LYP/6-311G** level of theory and the solvent (dichloromethane) contribution was estimated by using the recently developed SM5.43R solvation model. DFT calculations were first carried out to determine the energy profiles associated with the electrocyclization reactions of 3-hydroxy- and 3-ethoxypentadienyl cations in which one of the double bonds is embedded in O-heterocyclic and carbocyclic systems. In particular, the effects on the reaction rate of modifications to the substrate, as well as the presence of the heteroatom in the cycle, have been investigated. The torquoselectivity of the electrocyclization reaction was then explored with substituted O-heterocycles to understand the factors that control the stereochemical outcome of the process that preferentially provides 2,5-trans-disubstituted products. These DFT-based results rationally explain most of the experimental observations related to the Nazarov reaction of the substrates herein investigated and could be useful in the rational interpretation, and likely in the prediction, of the outcome of Nazarov reactions involving other cyclic systems.

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Section: Resultsmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

Density Functional Studies on the Nazarov Reaction Involving Cyclic Systems

Cavalli

Masetti

Recanatini

et al. 2006

Chemistry A European J

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“…The Nazarov reaction belongs to the class of electrocyclic reactions and its synthetic utility has been widely demonstrated by the straightforward syntheses of a number of five-membered rings, some of which were identified in the structures of important natural products. [66,67] While the asymmetric metal-catalyzed variant of the Nazarov reaction of divinylketones typically provided trans-cyclopen- tenones (by a conrotatory ring closure),…”

Section: Methodsmentioning

confidence: 99%

Asymmetric Organocatalysis: From Infancy to Adolescence

2008

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After an initial period of validating asymmetric organocatalysis by using a wide range of important model reactions that constitute the essential tools of organic synthesis, the time has now been reached when organocatalysis can be used to address specific issues and solve pending problems of stereochemical relevance. This Review deals with selected studies reported in 2006 and the first half of 2007, and is intended to highlight four main aspects that may be taken as testimony of the present status and prospective of organocatalysis: a) chemical efficiency; b) discovery of new substrate combinations to give new asymmetric syntheses; c) development of new catalysts for specific purposes by using mechanistic findings; and d) applications of organocatalytic reactions in the asymmetric total synthesis of target natural products and known compounds of biological and pharmaceutical relevance.

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“…[4,[6][7][8] Some catalyzed sigmatropic shifts have also been described. [7,9] However, aside from Nazarov cyclizations (fourelectron electrocyclizations in which oxy-pentadienyl cations are generated in situ), [10] electrocyclizations have generally resisted catalysis. Recently, though, Bergman, Trauner, and co-workers have demonstrated for the first time that sixelectron electrocyclizations can be catalyzed by Lewis acids (Scheme 1).…”

mentioning

confidence: 99%

Using Theory and Experiment to Discover Catalysts for Electrocyclizations

Tantillo

2008

Angew Chem Int Ed

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Some New Nazarov Chemistry

Cited by 344 publications

References 69 publications

Density Functional Studies on the Nazarov Reaction Involving Cyclic Systems

Density Functional Studies on the Nazarov Reaction Involving Cyclic Systems

Asymmetric Organocatalysis: From Infancy to Adolescence

Using Theory and Experiment to Discover Catalysts for Electrocyclizations

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