Microwave-Assisted Claisen and Aza-Claisen Rearrangements

Tymoshenko, Dmytro O.

doi:10.2174/157019308784223587

Cited by 19 publications

(7 citation statements)

References 68 publications

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“…This requirement is often fulfilled with rearrangements proceeding via cyclic transition states and with sigmatropic rearrangements which represent stereospecific transformations. Typical examples are Cope and Claisen rearrangements and variations like Claisen-Ireland, Claisen-Johnsen, Meerwein-Eschenmoser-Claisen, thio- and aza-Claisen, and Carrol rearrangement [ 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 ]. A special situation arises when atropisomeric biaryls are involved translating axial-chirality of the substrates into centro-chirality of the products provided the reaction proceeds at a temperature where no racemisation of the biaryl takes place.…”

Section: Introductionmentioning

confidence: 99%

Tandem RCM–Claisen Rearrangement–[2+2] Cycloaddition of O,O'-(But-2-en-1,4-diyl)-bridged Binaphthols

et al. 2012

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Section: Introductionmentioning

confidence: 99%

Tandem RCM–Claisen Rearrangement–[2+2] Cycloaddition of O,O'-(But-2-en-1,4-diyl)-bridged Binaphthols

et al. 2012

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“…The Cope rearrangement as a formal [3,3]‐sigmatropic reaction of a 1,5‐hexadiene moiety to its degenerate isomer embodies a fundamental reaction in organic chemistry that launched heated discussions concerning its mechanism, leading to a multitude of studies and reviews in the past 40 years 1–5. This prototypical reaction is ubiquitously used in various synthetic applications,6–9 e.g., in the synthesis of natural products, fragrances, and flavor compounds, and is a key reaction in biological processes 10. Besides experimental studies, the Cope reaction has been a hot topic in theoretical investigations, as well as in discussions about the benchmarking of computational methods 11–15.…”

Section: Introductionmentioning

confidence: 99%

The Cope rearrangement—the first born of a great family

Graulich

2011

WIREs Comput Mol Sci

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This review takes the experimental and theoretical discussions on the Cope rearrangement as the basis to emphasize its tight connection to many closely related pericyclic reactions. The Cope reaction, which is rather simple in a formal sense, has led to a plethora of mechanistic discussions to determine the nature of biradical-like intermediates or transition structures. After intense experimental and theoretical investigations starting in the late 1960s, the Cope rearrangement turned out to be a multifaceted reaction with a 'chameleonic' nature, ranging from homoaromatic transition structures to biradical intermediates in substituted cases, and six-electron transition states in the parent system. Additionally, the Cope rearrangement served as an excellent example to probe theoretical methods for the computations of a variety of pericyclic reactions. However, the relationship of the Cope rearrangement with analogous reactions has been hampered by the notion that pericyclic reactions typically are assumed to proceed in a concerted fashion. Only in the past 10 years, the Cope reaction, with its 1,5hexadiene unit, emerged as the structural and mechanistic prototype of a large family, including sigmatropic, cycloaddition, and other electrocyclic reactions as well as thermal rearrangements of polyunsaturated systems, enediynes, eneyneallenes, and many others. The recurrent and interconnecting motif in this family of reactions is the questions regarding cyclic aromatic transition states and the possible involvement of biradical intermediates.

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“…Compound 12 was used as a model system, and was submitted to microwave irradiation and underwent a Claisen rearrangement within 2 h to give 16 in 80% yield (Scheme 3). 13 In a further step, the isomerization of this compound was also tested. First, the free phenol 16 was protected using dimethylsulfate in 43% yield, then 2,4-dimethoxy-6-allylanisole (17) in THF was heated to reflux for 16 h in the presence of potassium-tert-butoxide.…”

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confidence: 99%