Anna G. Larina

Reaction of vinylidenecyclopropanes with aromatic imines in the presence of Lewis acids

Abstract1-Methyl-2-(2-methylpropenylidene)-1-phenylcyclopropane, 7-(2-methylpropenylidene)bicyclo[4.1.0]heptane, and (Z)-9-(2-methylpropenylidene)bicyclo[6.1.0]non-4-ene react with N-benzylideneanilines in the presence of boron trifluoride-ether complex to give pyrrolidine derivatives. Reactions of 1-methyl-1-phenyl-2-diphenylvinylidenecyclopropane with N-benzylideneanilines in the presence of BF3·Et2O, Yb(OTf)3, or Sc(OTf)3 lead to the formation of substituted 1,2,3,4-tetrahydroquinolines. 7-Diphenylvinylidenebicyclo[4.1.0]heptane in the presence of BF3·Et2O undergoes isomerization into 5-phenyl-8,9,10,11-tetrahydro-7H-cyclohepta[a]naphthalene.

Synthesis of Functionalized 3-Spiro[cyclopropa[a]pyrrolizine]- and 3-Spiro[3-azabicyclo[3.1.0]hexane]oxindoles from Cyclopropenes and Azomethine Ylides via [3 + 2]-Cycloaddition

3-Spiro[cyclopropa[a]pyrrolizine]- and 3-spiro[3-azabicyclo[3.1.0]hexane]oxindoles were prepared in moderate to high yields via one-pot three-component reactions using substituted isatins, α-amino acids, and cyclopropenes. The key step is an intramolecular [3 + 2]-cycloaddition reaction of an in situ generated azomethine ylide onto a cyclopropene. Both N-substituted and N-unsubstituted α-amino acids, dipeptide Gly-Gly, and also benzylamine were used as the amine component for the azomethine ylide generation. The anticancer activity of some of the obtained compounds against human leukemia K562 cell line was evaluated by flow cytometry in vitro.

Reduction of 7-aryl-6,8-dioxo-2-oxa-3,7-diazabicyclo[3.3.0]oct-3-ene-4-carboxylic and 7-aryl-6,8-dioxo-1-oxa-2,7-diazaspiro[4.4]non-2-ene-3-carboxylic acid esters

Ethyl 7-aryl-6,8-dioxo-2-oxa-3,7-diazabicyclo[3.3.0]oct-3-ene-4-carboxylates and ethyl 7-aryl-6,8-dioxo-1-oxa-2,7-diazaspiro[4.4]non-2-ene-3-carboxylates were selectively reduced with sodium tetrahydridoborate at the carbonyl group in the β-position with respect to the oxygen atom in the isoxazole ring.

Regio- and stereoselective (3 + 2)-cycloaddition of nitrile oxides and nitrones to N -vinylindole

Abstract1,3-Dipolar cycloaddition of nitrile oxides and nitrones to N-vinylindole proceeds regioselectively at the exocyclic multiple bond to form 5-indolyl-substituted isoxazolines and isoxazolidines in good yields.

Reaction of 6,6-dimethylfulvene with aromatic imines in the presence of Lewis acids

Formal aza-Diels-Alder (Povarov) reaction of 6,6-dimethylfulvene with aromatic imines is described for the first time.

Synthesis of Isoxazolopyrrolo[2,1-a]isoquinoline, Isoxazolo[5′,4′: 1,2]indolizino[8,7-b]indole, and Isoxazolo-[5,4-a]thieno[2,3-g]indolizine Derivatives by Intramolecular Cyclization of Hydroxylactams Constituting a Fragment of the Pyrroloisoxazole System

Abstract6-Hydroxy-5-[2-(naphthalen-1-yl)ethyl]-3a,5,6,6a-tetrahydro-4H-pyrrolo[3,4-d]isoxazol-4-ones in the presence of boron trifluoride–diethyl ether complex underwent cyclization to benzo[f]isoxazolo[5′,4′: 3,4]- pyrrolo[2,1-a]isoquinoline derivatives as mixtures of two diastereoisomers. Analogous cyclization of 6-hydroxy- 5-(naphthalen-1-ylmethyl)-3a,5,6,6a-tetrahydro-4H-pyrrolo[3,4-d]isoxazol-4-ones gave benzo[de]isoxazolo[ 5′,4′: 3,4]pyrrolo[2,1-a]isoquinolines as a single diastereoisomer. The cyclization of 6-hydroxy-5-[2-(1Hindol- 3-yl)ethyl]-6,6a-dihydro-3aH-pyrrolo[3,4-d]isoxazol-4(5H)-ones catalyzed by Sn(NTf2)4 afforded isoxazolo[ 5′,4′: 1,2]indolizino[8,7-b]indol-4(12H)-ones in moderate yields. 6-Hydroxy-5-[2-(thiophen-2-yl)ethyl]-6,6a-dihydro-3aH-pyrrolo[3,4-d]isoxazol-4(5H)-ones were converted to 4,5,10a,10b-tetrahydroisoxazolo- [5,4-a]thieno[2,3-g]indolizin-7(7aH)-one derivatives in the presence of BF3 · Et2O or Sn(NTf2)4.

A highly diastereoselective one-pot three-component 1,3-dipolar cycloaddition of cyclopropenes with azomethine ylides generated from 11H-indeno[1,2-b]-quinoxalin-11-ones

A simple and efficient method has been developed for the synthesis of complex compounds with spiro-fused 11H-indeno[1,2-b]quinoxaline and cyclopropa[a]pyrrolizine or azabicyclo[3.1.0]hexane moieties. All the products have been synthesized in good to high yields and excellent diastereoselectivity by one-pot three-component 1,3-dipolar cycloaddition reactions of various derivatives of cyclopropene with azomethine ylides. Azomethine ylides were in situ generated from 11H-indeno[1,2-b]quinoxalin-11-one derivatives and amines, such as N-substituted and N-unsubstituted α-amino acids, benzylamines, and also peptides (dipeptide Gly-Gly and tripeptide Gly-Gly-Gly). To understand the mechanism that allows for azomethine ylide generation followed by 1,3-dipolar cycloaddition, a quantum chemical investigation was performed. The anticancer activity of some of the obtained compounds against the human leukemia K562 cell line was evaluated by flow cytometry in vitro.

Isomerization of dimethylenecyclopropanes in benzofulvenes in the presence of Lewis acids

Abstract1,1-Diaryl-2-(1-methylethylidene)-3-methylenecyclopropanes in the presence of Lewis acid isomerize in benzofulvene derivatives.