Regio- and Enantioselective Cyclobutene Allylations

Niyomchon, Supaporn; Luparia, Marco; Maulide, Nuno

doi:10.1021/ol401033g

Cited by 30 publications

(15 citation statements)

References 28 publications

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“…Further examples of transformations of this type were reported by Maulide and co-workers starting from strained bicylic lactones to provide geminal or vicinal disubstituted cyclobut-3-enes ( Scheme 149 ). 446 …”

Section: Asymmetric Allylic Substitutionmentioning

confidence: 99%

Recent Advances in Enantioselective Pd-Catalyzed Allylic Substitution: From Design to Applications

Pàmies

Margalef

Cañellas³

et al. 2021

Chem. Rev.

410

202

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This Review compiles the evolution, mechanistic understanding, and more recent advances in enantioselective Pd-catalyzed allylic substitution and decarboxylative and oxidative allylic substitutions. For each reaction, the catalytic data, as well as examples of their application to the synthesis of more complex molecules, are collected. Sections in which we discuss key mechanistic aspects for high selectivity and a comparison with other metals (with advantages and disadvantages) are also included. For Pd-catalyzed asymmetric allylic substitution, the catalytic data are grouped according to the type of nucleophile employed. Because of the prominent position of the use of stabilized carbon nucleophiles and heteronucleophiles, many chiral ligands have been developed. To better compare the results, they are presented grouped by ligand types. Pd-catalyzed asymmetric decarboxylative reactions are mainly promoted by PHOX or Trost ligands, which justifies organizing this section in chronological order. For asymmetric oxidative allylic substitution the results are grouped according to the type of nucleophile used.

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Section: Asymmetric Allylic Substitutionmentioning

confidence: 99%

Recent Advances in Enantioselective Pd-Catalyzed Allylic Substitution: From Design to Applications

Pàmies

Margalef

Cañellas³

et al. 2021

Chem. Rev.

410

202

View full text Add to dashboard Cite

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“…Synthesis of these cyclobutene lactones by the disrotatory 4‐pi photoelectrocyclization of 2‐pyrone derivatives has become well established, since its first report by Corey in 1964 . As a piece of classical photochemistry, this has been examined with a variety of coumalic esters, and other substituted 2‐pyrones, resulting in valuable starting materials for the aforementioned chemistries (Scheme ). However, as with many classical photochemical methodologies, the equipment and methods used to carry out these reactions have not changed since their first discovery and still generally consist of immersion well glassware, with a pressurized mercury lamp, whereby the only control over emission wavelength is achieved by application of various band‐pass or exclusion filters.…”

Section: Methodsmentioning

confidence: 99%

Towards a Scalable Synthesis of 2‐Oxabicyclo[2.2.0]hex‐5‐en‐3‐one Using Flow Photochemistry

et al. 2019

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Cyclobutene lactones hold great potential as synthetic building blocks, yet their preparation by photochemical rearrangement in batch can often be a bottleneck in synthetic studies. We report the use of flow photochemistry as a tool to enable a higher‐throughput approach to the synthesis of 2‐oxabicyclo[2.2.0]hex‐5‐en‐3‐one, which reduces reaction times from 24 h to 10 min. Accordingly, a significantly improved throughput of 144 mg/h (vs 14–21 mg/h in batch) was achieved. Scale‐out experiments showed problematic reactor fouling and steps were taken to explore and minimize this effect.

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“…Synthesis and versatile chemistry of cyclobutene lactones 213. [74,[76][77][78][79][80][81] sides stabilized nucleophiles like malonates and azlactones, non-stabilized allylpinacaol boronates were employed to afford cyclobutene derivatives 216. [78] Simple alkyl-217 or halogensubstituted cyclobutene derivatives 218 were obtained by reaction with organocopper reagents [79] or alkali halide salts.…”

Section: [2 + 2]-cycloadditionmentioning

confidence: 99%

2‐Pyrone – A Privileged Heterocycle and Widespread Motif in Nature

et al. 2021

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In memory of Klaus HafnerThe 2-pyrone moiety can be found in a large number of natural products with a wide range of biological activities, including antibiotic, antifungal, cytotoxic, neurotoxic, phytotoxic, antiinflammatory and cardiotonic effects. With its heterocyclic structure encompassing the chemical nature of conjugated dienes, lactones, Michael acceptors and arenes, it can undergo a great variety of transformations such as cycloadditions, ringopening reactions, cross-couplings and lactamizations. Thus, 2-pyrones represent valuable synthetic precursors and worthwhile targets in organic, polymer, and medical chemistry. Owing to its exquisite chemical and physical properties, the synthesis and further transformations of 2-pyrones have attracted considerable attention over the past decade, showcasing transition metal and metal free strategies and using readily available starting materials, notably those stemming from renewable resources.

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Regio- and Enantioselective Cyclobutene Allylations

Abstract: Catalytic asymmetric allylation of lactone 1 with allyl boronates leads to functionalized cyclobutenes in high regio- and stereoselectivity.

Cited by 30 publications

References 28 publications

Recent Advances in Enantioselective Pd-Catalyzed Allylic Substitution: From Design to Applications

Recent Advances in Enantioselective Pd-Catalyzed Allylic Substitution: From Design to Applications

Towards a Scalable Synthesis of 2‐Oxabicyclo[2.2.0]hex‐5‐en‐3‐one Using Flow Photochemistry

2‐Pyrone – A Privileged Heterocycle and Widespread Motif in Nature

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