Elena I. Klimova

The structure of bicyclic ferrocenylmethylene substituted 2-pyrazolines and their reactions with azodicarboxylic acid N-phenylimide

Abstract Asymmetrical induction in the synthesis of bicyclic pyrazolines with a ferrocenyl substituent has been studied. A relatively high diastereomeric selectivity in the ‘chiral-center-by-a-chiral-center’ induction of the 1,2-type has been observed. Molecular geometry of a cis -diastereomer of 1-acetyl-9-ferrocenyl-4-ferrocenylmethylene-1,2-diazabicyclo[4.3.0]non-2-ene has been established. Bicyclic 2-pyrazolines having conjugated ferrocenylmethylene fragments interact with azodicarboxylic acid N -phenylimide to form diene and monoene adducts.

Cyclodimerization of the 1-methyl-1,3-diferrocenylallyl cation into 1,3,5-triferrocenyl-4-(1-ferrocenylethenyl)cyclohexene

An unusual cyclodimerization reaction of the 1-methyl-1,3-diferrocenylallyl cation into 1,3,5-triferrocenyl-4-(1-ferrocenylethenyl)cyclohexene has been studied. Two isomeric compounds were isolated and their structures were established as 1,r3,c5-triferrocenyl-4-t-(1-ferrocenylethenyl)cyclohexene and 1,r3, t5-triferrocenyl-4-c-(1-ferrocenylethenyl)cyclohexene on the basis of 1H NMR and 13C NMR spectral data.

The reactions of semicarbazide and thiosemicarbazide with ferrocenyl-substituted α,β-enones

Abstract Semicarbazide (hydrochloride) and thiosemicarbazide react with α,β-unsaturated ketones of the ferrocene series in excess of t BuOK to give 1-carbamoyl- and 1-thiocarbamoyl(ferrocenyl)-4,5-dihydropyrazoles. The condensation with thiosemicarbazide is accompanied by the fragmentation of the starting α,β-enones resulting in ferrocenecarbaldehyde or acetylferrocene thiosemicarbazones.

Solvent-free aldol condensations: synthesis of ferrocenyldienones

The aldol condensation of ferrocenecarbaldehyde and acetylferrocene with aldehydes and ketones proceeded more efficiently and stereoselectively in the absence of a solvent than in solution. In all the cases, E-configured enones were obtained, which was confirmed by X-ray crystallographic studies of one of the products.

Stereoselectivity of formation of polycyclic ferrocenyl-4,5-dihydropyrazoles based on E- and Z-s-cis-α,β-enones

Abstract Reaction of E- and Z-isomeric 2-ferrocenylmethylidene-1-tetralone, 2-ferrocenylmethylidene-3-quinuclidinone, 1-methyl-3-ferrocenylmethylidene-4-piperidone and 2-ferrocenylmethylidenetropinone with hydrazine proceeds stereospecifically with the formation of the same diastereomeric polycyclic ferrocenyldihydropyrazoles independently of the geometric configuration of the starting α,β-unsaturated ketones. X-ray structural analysis is presented for the trans-diastereomer of 4-acetyl-3-ferrocenyl-1,4,5-triazatricyclo[5.2.2.02,6]undec-5-ene.

Regioselectivity of alkylation of the naphthalene fragment in the opening of a small ring in 3-ferrocenyl-3-(1-naphthyl)cyclopropene, Z-2-bromo-1-ferrocenyl-1-(1-naphthyl)cyclopropane, and 1-ferrocenyl-1-(1-naphthyl)cyclopropane

Abstract The opening of a small ring in 3-ferrocenyl-3-(1-naphthyl)cyclopropene (thermolysis, action of HBF4·Et2O or CF3SO3H), Z-2-bromo-1-ferrocenyl-1-(1-naphthyl)cyclopropane (action of AlCl3), and in 1-ferrocenyl-1-(1-naphthyl)cyclopropane (action of Ph3C+BF4−) is accompanied by the alkylation of only the naphthalene fragment giving rise to 1-ferrocenyl-9bH-benzo[e]indene or 1-ferrocenyl-3H-benzo[e]indene. This is connected with a ‘non-bisecting’ position of the naphthalene fragment relative to the three-membered cycle in the starting compounds. The compound 1-ferrocenyl-9bH-benzo[e]indene gives [4+2]-cycloadducts with N-phenyl(azodicarboximide) and N-phenylmaleimide. X-ray structural data are presented for 3-ferrocenyl-3-(1-naphthyl)cyclopropene and its adduct with 1,3-diphenylisobenzofuran, Z-2-bromo-1-ferrocenyl-1-(1-naphthyl)cyclopropane, and 1-ferrocenyl-1-(1-naphthyl)cyclopropane.

Synthesis and some chemical properties of 3-ferrocenyl-3-isopropylcyclopropene: 3-ferrocenyl-3-isopropylstructures of cyclopropene and its adducts with 1,3-diphenylisobenzofuran

Abstract X-ray structural analysis allowed the molecular conformation of 3-ferrocenyl-3-isopropylcyclopropene to be established, where the ferrocenyl fragment occupies a bisecting position relative to the three-membered ring. Some heterolytic cleavage of a σ CC bond in cyclopropene was observed. As a result, predominantly linear products are formed: 1,1-dimethyl-2-ferrocenyl-1,3-butadiene, 3-ferrocenyl-4-methyl-2-pentene, 3-ferrocenyl-4-methyl-3-pentenine and also 3-isopropyl-1H-cyclopentaferrocene. Cyclopropene forms a classical Diels–Alder adduct with 1,3-diphenylisobenzofuran and an adduct with the intermediate 3-isopropyl-1,2-(1-propene-1,3-diyl)ferrocene. X-ray structural data of exo -1,5-diphenyl-3- anti -ferrocenyl-3- syn -isopropyl-6,7-benzo-8-oxatricyclo[3.2.1.0 2,4 ]oct-6-ene are presented.

Formation of acetylenic compounds and ring transformations of 3-alkyl-3-ferrocenylcyclopropenes in the reaction with 1,3-diphenylisobenzofuran

The reaction of 3-ferrocenyl-3-methylcyclopropene with 1,3-diphenylisobenzofuran leads to the formation of exo - and endo -1,4-epoxy-2-ethynyl-2-ferrocenyl-1,4-diphenyltetralines as the main products in addition to the isomeric Diels–Alder exo -adducts. At the same time, 3- tert -butyl- and 3-(1-adamantyl)-3-ferrocenylcyclopropenes form the endo - and exo -adducts of 3-alkyl-1,2-(1-propene-1,3-diyl)ferrocene. The structures of the acetylenic compounds and of the adduct containing a t Bu-substituent are established by X-ray structural analysis. A possible reaction pathway via intermediate zwitter-ion is discussed.

STRUCTURE OF Z- AND E-2-BROMO-1-FERROCENYL-1-PHENYLCYCLOPROPANES AND 3-FERROCENYL-3-PHENYLCYCLOPROPENE AND THEIR THREE-MEMBERED RING OPENING REACTIONS

Abstract The ring-opening reactions in Z - and E -2-bromo-1-ferrocenyl-1-phenylcyclopropanes and 3-ferrocenyl-3-phenylcyclopropene were studied. It was found that the three-membered ring of the monobromides is opened when treated with AlCl 3 , while that of cyclopropene is opened when boiled in toluene. X-ray structural data of E -2-bromo-1-ferrocenyl-1-phenyIcyclopropane and 3-ferrocenyl-3-phenyl-cyclopropene mono crystals are presented.

The behaviour of 2-methylene-3-ferrocenylmethylenecamphane under conditions leading to the cyclodimerization of ferrocenyl-1,3-butadienes

The behaviour of 2-methylene-3-ferrocenylmethylenecamphane under proton cyclodimerization conditions has been investigated. The stage involving the formation of the dimeric linear allylic cation has been confirmed in these interactions by isolating of corresponding diene. Its structure has been established unambiguously by X-ray methods. All substances isolated have been characterized by elemental analyses and 1H and 13C NMR spectral data.