Room-Temperature B(OAc)3-Promoted Diels–Alder Reaction of Juglone with Styrenes: Total Syntheses of Tetrangulol and Anhydrolandomycinone

2012 ◽  
Vol 77 (6) ◽  
pp. 2659-2666 ◽  
Author(s):  
Day-Shin Hsu ◽  
Jiun-Yi Huang
Keyword(s):  
Room Temperature ◽  
Alder Reaction ◽  
Diels Alder ◽  
Total Syntheses ◽  
Diels Alder Reaction

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.

Total syntheses of ericifolione and analogues via a biomimetic inverse-electron-demand Diels-Alder reaction

2021 ◽  
Author(s):  
Tingting Zhou ◽  
Anquan Zheng ◽  
Luqiong Huo ◽  
Changgeng Li ◽  
Haibo Tan ◽  
...  
Keyword(s):  
Sodium Acetate ◽  
Alder Reaction ◽  
Diels Alder ◽  
Total Syntheses ◽  
Inverse Electron Demand ◽  
Diels Alder Reaction ◽  
Sterically Hindered ◽  
Electron Demand

Driven by bioinspiration and appreciation of the structure of ericifolione, a biomimetic tautomerization/intermolecular inverse-electron-demand hetero Diels-Alder reaction cascade sequence promoted by sodium acetate to rapidly construct sterically hindered dihydropyran scaffolds...

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%.

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