Phase-transfer-catalyzed cyclization reaction of nucleophilic addition to electron-deficient 1,3-conjugated enynes for the synthesis of functionalized 4H-pyrans.
نویسندگان
چکیده
A variety of substituted 4H-pyrans are readily prepared in moderate to good yields under the mild reaction conditions by nucleophilic addition to electron-deficient 1,3-conjugated enynes with phase-transfer catalysis (PTC).
منابع مشابه
Lactic acid-catalyzed Eco-friendly Cyclization Reaction for the Synthesis of 4H-benzo[b]pyrans and 3,4-dihydropyrano[c]chromenes in EtOH/H2O as an Efficient Green Reaction Medium
An environmentally friendly, green, and highly efficient process for the synthesis of biologically and pharmacologically 4H-benzo[b]pyrans and 3,4-dihydropyrano [c] chromenes is developed by condensing cyclic aromatic aldehydes, malononitrile, and dimedone or 4‐hydroxycoumarin in the presence of lactic acid as an efficient and green catalyst. The corresponding products have b...
متن کاملDBU-catalyzed tandem additions of electron-deficient 1,3-conjugated enynes with 2-aminomalonates: a facile access to highly substituted 2-pyrrolines.
An efficient, metal free approach to highly substituted 2-pyrrolines by DBU-catalyzed tandem additions (a formal [3+2] cycloaddition) of electron-deficient 1,3-conjugated enynes and 2-aminomalonates under mild conditions was developed.
متن کاملSynthesis of 4-methylene-4H-benzo[d][1,3]thiazines via a tandem reaction of 1-(2-alkynylphenyl)ketoximes with Lawesson's reagent.
1-(2-Alkynylphenyl)ketoximes react with Lawesson's reagent catalyzed by InCl(3) and cyanuric chloride leading to 4-methylene-4H-benzo[d][1,3]thiazines in good yields. This tandem reaction proceeds with high efficiency through Beckmann rearrangement, thioamide formation, and intramolecular nucleophilic cyclization.
متن کاملGold-catalyzed cycloisomerization of alk-4-yn-1-ones.
Depending on the substitution pattern and the solvent, the gold-catalyzed cyclization of alk-4-yn-1-ones affords different oxygen heterocycles under mild reaction conditions. Alkynones with one substituent at C-3 undergo a 5-exo-dig cycloisomerization to substituted furans , whereas a 6-endo-dig cyclization to 4H-pyrans is observed with substrates bearing two substituents at C-3. In alcoholic s...
متن کاملPorous Acidic Catalyst, Functionalized with Imidazole Ionic Liquid ([SBA-Im]HSO4) as a Novel Phase Transfer Catalyst for The Aqueous Synthesis of Benzyl Thiocyanates and Azides
In the present study, application of porous acidic catalyst functionalized with an imidazoleionic liquid ([SBA-Im]HSO4) as a phase transfer catalyst for the facile preparation of benzylthiocyanates and azides in water has been described. The catalyst has been characterized byFourier transform infrared spectroscopy (FT-IR), scanning electron microscope (SEM), transmissionelectron microscopy (TEM...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- Organic & biomolecular chemistry
دوره 9 9 شماره
صفحات -
تاریخ انتشار 2011