نتایج جستجو برای: intramolecular michael
تعداد نتایج: 36937 فیلتر نتایج به سال:
Acyl transfer-enabled catalytic asymmetric Michael addition of α-hydroxy-1-indanones to nitroolefins
We report herein an enantioselective acyl transfer protocol via electrophile activation. The reaction cascade sequence encompasses dinuclear zinc-catalyzed asymmetric Michael addition, intramolecular cyclization, and retro-Claisen reaction, which leads to a step- atom-economic approach variety of protected cyclic tertiary α-hydroxyketones in good yields with excellent enantioselectivities (24 e...
A transition-metal-free and base-promoted one-pot reaction of ynones with 2-aminobenzonitriles is described. The was initiated through sequential aza-Michael addition/intramolecular annulation to afford various multisubstituted 4-aminoquinolines 4-amino-1,8-naphthyridines in good excellent yields. Operational simplicity, high atom-economy broad substrate scope makes this protocol more attractiv...
Abstract: This lecture describes some of our studies of lithio derivatives of allyl sulfone carbanions which add α-regioselectively as well as anti diastereoselectively to Michael acceptor olefins. This can be ascribed to chelation in the Michael addition step. When the reaction leads to subsequent ring closure by using a bromoallyl sulfone, the latter acts as a methylenemethane synthon in a (3...
Abstract The base-catalyzed reaction of diethyl 1,3-acetonedicarboxylate with 2-hydroxybenzylidene indenediones was studied. provides a facile and expeditious protocol for the synthesis natural product inspired fluorenone-fused coumarins in good to very yields. This process resembles combination domino Michael–intramolecular Knoevenagel–aromatization–lactonization reactions single step. Althoug...
Ethyl 2-[2-(4-nitrobenzoyl)-1H-indol-3-yl]acetate was prepared in good yield and characterized by the aza-alkylation/intramolecular Michael cascade reaction of (E)-ethyl 3-[2-(tosylamino)phenyl]acrylate with 2-bromo-4′ ′-nitroacetophenone, followed by desulfonative dehydrogenation with 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) The structure of the newly synthesized compound was determined using ...
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