نتایج جستجو برای: intramolecular cyclization
تعداد نتایج: 18338 فیلتر نتایج به سال:
A concise, diastereoselective total synthesis of (±)-cortistatin J has been completed in 20 steps from furan. Key steps include an intramolecular [4 + 3] cyclization of a disubstituted furan with a (Z)-2-(trialkylsilyloxy)-2-enal to construct the tetracyclic core and a (Z)-vinylsilane/iminium ion cyclization to form the A ring.
A novel protecting group directed diversity leading to the synthesis of bridged bicyclic and six-membered iminocyclitols from a common carbohydrate derived diamino triol under Mitsunobu conditions is reported. When the intramolecular cyclization of benzoyl derivative 16 was carried out under Mitsunobu conditions, an unprecedented one-pot domino intramolecular "cyclization-N→O benzoyl migration-...
A [Ir(ppy)2(dtb-bpy)]PF6-catalyzed intramolecular radical cyclization of o-iodophenylacrylamides affording indolin-2-ones in moderate to excellent yields via 5-exo-trig radical cyclization under visible light is presented. This method provides new access to the synthesis of indolin-2-ones under mild reaction conditions.
A strategy for synthesizing highly functionalized cyclohepta[b]indoles through a concise (4 + 3) cycloaddition-cyclization-elimination sequence is described. The cycloaddition features nitrogen-stabilized oxyallyl cations derived from epoxidations of N-aryl-N-sulfonyl-substituted allenamides, while the cyclization and elimination employed an intramolecular Grignard addition and a one-step Chuga...
The preparation of the diastereomerically pure beta-tetralone ketal 4 is reported. Intramolecular alkylidene C-H insertion followed by hydrolysis of 4 proceeded to give the enantiomerically pure cyclopentene 15. The key step in this synthesis was the bis-intramolecular cyclization of keto aldehyde 2 to give the tetracyclic intermediate 20. Enone 20 was converted over several steps to (-)-morphi...
A mild electrochemical method for the regioselective preparation of 1-tetralones under environmentally friendly conditions from readily available cyclobutanols was developed. series aromatic- and heteroaromatic-fused accessed through ring expansion functionalized via generation alkoxy radicals intramolecular cyclization.
Isoindoloisoquinalinone, pyrroloisoquinolinone and benzo[a]quinolizinone units are constructed via intramolecular cyclization of the methoxy substituted N-phenethylimides using BBr(3).
Nitrogen-bridged donor-acceptor multifused dithienopyrrolobenzothiadiazole (DTPBT) and dibenzothiadiazolopyrrolothiophene (DBTPT) were successfully synthesized by intramolecular Cadogan annulation. The electron-deficient benzothiadiazole unit in DTPBT can be converted to benzoselenadiazole and quinoxaline moieties through reduction/cyclization to generate dithienopyrrolobenzoselenadiazole (DTPB...
chromanone derivatives demonstrate remarkable cytotoxity against a varieties of cancer cell lines. novel 9-[hydroxy(substitutedphenyl)methyl]-2,2-dimethyl-2,3,8,9- tetrahydro-4h,10h-pyrano[2,3-f]chromene-4,10-diones as glyasperin analogues were synthesized in four steps from known 4-chromone 1. the key step was the preparation of chromane dione 5a by regioselective intramolecular cyclization re...
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