Silver(I)‐Catalyzed Intramolecular Cyclizations of Epoxide‐Propargylic Esters to 1,4‐Oxazine Derivatives
نویسندگان
چکیده
An interesting silver(I)-catalyzed, one-pot intramolecular cyclization of epoxide-propargylic esters is described. A variety of 1,4-oxazine derivatives were obtained through a novel domino sequence, including three-membered ring-opening, 3,3-sigmatropic rearrangement, 6-exo-cycloisomerization and subsequent intramolecular elimination in moderate yields under mild conditions.
منابع مشابه
Gold‐Catalyzed Intramolecular Cyclizations of Cyclopropenes with Propargylic Esters
Homogeneous gold catalysts are interesting as they can act as potent carbophilic Lewis acids to activate the π bonds of alkynes, allenes, and alkenes. Many impressive applications for the formation of C-C or C-heteroatom bonds have been found due to the excellent functional group compatibility of these catalysts and the air and moisture tolerance of their reactions. Here, we have developed gold...
متن کاملSilver(I)-catalyzed annulation for the regioselective synthesis of N-imino-γ-carbolinium ylides from hydrazones of indole-3-carbonyl derivatives and propargylic alcohols.
A regioselective efficient synthetic approach to N-imino-γ-carbolinium ylides via AgOTf-catalyzed iminoannulation has been developed. This transformation proceeds via a silver(i) triflate-catalyzed consecutive Friedel-Crafts reaction/N-C bond formation sequence between the readily available indole derivatives and propargylic alcohols.
متن کاملSynthesis of α-Acyloxyketone Derivatives via the Platinum-Catalyzed Migration of Propargylic Esters.
The synthesis of α-acyloxyketones via the migration of a propargylic ester followed by the intramolecular nucleophilic addition of the resulting allene was achieved using a cationic platinum catalyst. The optimized conditions for this transformation were determined to be 3 mol% of Pt(cod)Cl2, 3 mol% of AgNTf2, and 3 eq of water in toluene at 100 °C, and these conditions were successfully applie...
متن کاملSynthesis of diverse indole-containing scaffolds by gold(I)-catalyzed tandem reactions of 3-propargylindoles initiated by 1,2-indole migrations: scope and computational studies.
Similar to propargylic carboxylates and sulphides, 3-propargylindoles undergo 1,2-indole migrations under cationic gold(I) catalysis. The intermediate Au-carbenoid complex may evolve through different pathways depending on the substituents at the propargylic and terminal positions of the alkyne moiety. Thus, 3-indenylindole derivatives were easily obtained through formal iso-Nazarov or Nazarov ...
متن کاملCyclization of free radicals at the C-7 position of ethyl indole-2-carboxylate derivatives: an entry to a new class of Duocarmycin Analogues.
Aryl free-radicals generated at the C-7 position of ethyl indole-2-carboxylates bearing N-allyl and propargylic groups triggered intramolecular cyclizations to furnish a new class of Duocarmycin analogues, formal ethyl pyrrolo[3,2,1-ij]quinoline-2- carboxylate derivatives, through the less favorable 6-endo-trig cyclization mode.
متن کامل