A reactive lactonic dienophile – 3-carbethoxy-5,5-dimethyl-2(5H)-furanone. Application to the synthesis of a monoterpenoid lactone

1982 ◽  
Vol 60 (7) ◽  
pp. 921-925 ◽  
Author(s):  
Hsing-Jang Liu ◽  
Eric N. C. Browne ◽  
Purushottam R. Pednekar
Keyword(s):  
Title Compound ◽  
Room Temperature ◽  
Alder Reaction ◽  
Diels Alder ◽  
Stannic Chloride ◽  
Lithium Iodide ◽  
Diels Alder Reaction ◽  
Reaction Region ◽  
Unsaturated Lactones

In contrast to the low dienophilicity generally observed for α,β-unsaturated lactones, the title compound 2 is shown to be a reactive dienophile. Under stannic chloride catalysis, it undergoes Diels–Alder reaction region- and stereoselectively with a variety of dienes at room temperature. The synthesis of (±)-o-mentha-1,3-dien-1→8-olide (20) has been achieved by a two-step sequence using lactone ester 2. Addition of 2 to 1-acetoxy-1,3-butadiene afforded epimeric acetoxy lactones 12 and 13 which were converted to the monoterpenoid lactone 20 by treatment with lithium iodide dihydrate in collidine.

scholarly journals Hetero-Diels–Alder reactions of hetaryl and aryl thioketones with acetylenic dienophiles

2015 ◽  
Vol 11 ◽  
pp. 576-582 ◽  
Author(s):  
Grzegorz Mlostoń ◽  
Paulina Grzelak ◽  
Maciej Mikina ◽  
Anthony Linden ◽  
Heinz Heimgartner
Keyword(s):  
High Pressure ◽  
Room Temperature ◽  
Thermal Conditions ◽  
Alder Reaction ◽  
Diels Alder ◽  
Hydrogen Shift ◽  
Diels Alder Reaction ◽  
Shift Sequence

Selected hetaryl and aryl thioketones react with acetylenecarboxylates under thermal conditions in the presence of LiClO4 or, alternatively, under high-pressure conditions (5 kbar) at room temperature yielding thiopyran derivatives. The hetero-Diels–Alder reaction occurs in a chemo- and regioselective manner. The initially formed [4 + 2] cycloadducts rearrange via a 1,3-hydrogen shift sequence to give the final products. The latter were smoothly oxidized by treatment with mCPBA to the corresponding sulfones.

scholarly journals Enhancing the reactivity of 1,2-diphospholes in cycloaddition reactions

2015 ◽  
Vol 11 ◽  
pp. 169-173 ◽  
Author(s):  
Almaz Zagidullin ◽  
Vasili Miluykov ◽  
Elena Oshchepkova ◽  
Artem Tufatullin ◽  
Olga Kataeva ◽  
...  
Keyword(s):  
Room Temperature ◽  
Cycloaddition Reaction ◽  
Alder Reaction ◽  
Diels Alder ◽  
Alkyl Halides ◽  
Ethyl Iodide ◽  
Para Position ◽  
Cycloaddition Reactions ◽  
Diels Alder Reaction ◽  
Heating Up

Two different approaches have been employed to enhance the reactivity of 1-alkyl-1,2-diphospholes – the introduction of electron-withdrawing groups either at the phosphorus atoms or in the para-position of the arene ring. The alkylation of sodium 1,2-diphospha-3,4,5-triphenylcyclopentadienide with alkyl halides Hal-CH2-R (R = CN, COOEt, OMe, CH2OEt) results in corresponding 1-alkyl-3,4,5-triphenyl-1,2-diphospholes (alkyl = CH2CN (1a), CH2COOEt (1b), CH2OMe (1c), and (CH2)2OEt (1d)), which spontaneously undergo the intermolecular [4 + 2] cycloaddition reactions at room temperature to form the mixture of the cycloadducts, 2a–c, respectively. However the alkylation of sodium 1,2-diphospha-3,4,5-tri(p-fluorophenyl)cyclopentadienide with ethyl iodide leads to stable 1-ethyl-3,4,5-tris(p-fluorophenyl)-1,2-diphosphole (1e), which forms the [4 + 2] cycloadduct 2,3,4,4a,5,6-hexa(p-fluorophenyl)-1-ethyl-1,7,7a-triphospha-4,7-(ethylphosphinidene)indene (2e) only upon heating up to 60 °C. With further heating to 120 °C with N-phenylmaleimide, the cycloadducts 2a–c and 2e undergo the retro-Diels–Alder reaction and form only one product of the [4 + 2] cycloaddition reaction 3a–с, 3e with good yields up to 65%.

scholarly journals A theoretical study of the solvent effect on Diels-Alder reaction in room temperature ionic liquids using a supermolecular approach

2009 ◽  
Vol 123 (3-4) ◽  
pp. 347-352 ◽  
Author(s):  
Riccardo Bini ◽  
Cinzia Chiappe ◽  
Veronica L. Mestre ◽  
Christian S. Pomelli ◽  
Thomas Welton
Keyword(s):  
Ionic Liquids ◽  
Solvent Effect ◽  
Room Temperature ◽  
Theoretical Study ◽  
Alder Reaction ◽  
Diels Alder ◽  
Room Temperature Ionic Liquids ◽  
Diels Alder Reaction

Synthesis of (±)-epiisopodophyllotoxin

1983 ◽  
Vol 61 (3) ◽  
pp. 573-575 ◽  
Author(s):  
Margaret B. Glinski ◽  
Tony Durst
Keyword(s):  
Title Compound ◽  
Dimethyl Fumarate ◽  
Dimethyl Acetal ◽  
Alder Reaction ◽  
Diels Alder ◽  
Carbon Skeleton ◽  
Diels Alder Reaction ◽  
Alder Adduct

The synthesis of (±)-epiisopodophyllotoxin commencing with 6-bromopiperonal dimethyl acetal is described. The carbon skeleton of isoepipodophyllotoxin was assembled via a Diels–Alder reaction between the hydroxyquinodimethane generated photochemically from 6-(3′,4′,5′-trimethoxybenzyl)-piperonal, obtained from the bromoacetal above, and dimethyl fumarate. This Diels–Alder adduct was converted in five steps into the title compound. The overall yield for the seven steps was 15%.

scholarly journals Ionic liquid promoted Diels-Alder Reaction between anthrone and maleimides

2010 ◽  
Vol 8 (2) ◽  
pp. 356-360 ◽  
Author(s):  
Nitin Mirgane ◽  
Sandip Kotwal ◽  
Anil Karnik
Keyword(s):  
Ionic Liquid ◽  
Ionic Liquids ◽  
Room Temperature ◽  
Alder Reaction ◽  
Dual Role ◽  
Diels Alder ◽  
Environmentally Benign ◽  
Green Solvents ◽  
Imidazolium Ionic Liquid ◽  
Diels Alder Reaction

AbstractIonic liquids (IL) are gaining importance as green solvents. Imidazolium ionic liquid [bmim]+[Cl]−, an environmentally benign solvent, was found to promote the Diels-Alder reaction between anthrone and maleimides at room temperature with excellent yields. The ionic liquid played a dual role as solvent and catalyst.

Regioselective Diels-Alder Reaction of 5-hydroxy-1,4-naphthoquinone with Isoprene at Room Temperature

10.1039/sp800 ◽  
2015 ◽  
Author(s):  
Andrew J. Smaligo ◽  
Jevica Salim ◽  
Steven M. Kennedy
Keyword(s):  
Room Temperature ◽  
Alder Reaction ◽  
Diels Alder ◽  
Diels Alder Reaction

Can a Diels–Alder reaction be accelerated in a supersaturated solvent at room temperature?

2016 ◽  
Vol 40 (10) ◽  
pp. 8355-8363 ◽  
Author(s):  
Amit S. Nagare ◽  
Arpan Manna ◽  
Anil Kumar
Keyword(s):  
Room Temperature ◽  
Alder Reaction ◽  
Diels Alder ◽  
Product Yields ◽  
Diels Alder Reaction

New carbohydrate-based supersaturated solvent for superior rates and high product yields.

scholarly journals Regiospecific synthesis of neuroprotective 1,4-benzoxazine derivatives through a tandem oxidation–Diels–Alder reaction

2015 ◽  
Vol 13 (12) ◽  
pp. 3749-3756 ◽  
Author(s):  
Khac Minh Huy Nguyen ◽  
Leslie Schwendimann ◽  
Pierre Gressens ◽  
Martine Largeron
Keyword(s):  
Room Temperature ◽  
Alder Reaction ◽  
Diels Alder ◽  
Diels Alder Reaction

Highly functionalized 1,4-benzoxazine derivatives have been synthesized at room temperature, with complete regiochemical control, through a tandem oxidation–Diels–Alder reaction.

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