Cyclopropanation of 2-arylmethylidenemalononitriles, alkyl 3-aryl-2-cyanoprop-2-enoates, and N-substituted 3-aryl-2-cyanoprop-2-enamides with bromine-containing zinc enolates

Abstract

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Reactions of bromine-containing organozinc compounds derived from α,α-dibromo ketones with 2-arylmethylideneindan-1,3-diones and 5-arylmethylidene-2,2-dimethyl-1,3-dioxane-4,6-diones

“…Cross-sections of the resulting two-dimensional spectrum that are parallel to the F1 axis and passing through signals of the corresponding carbon atoms give one-dimensional spectra displaying only coupling constants with the 3-H proton: 3 J(3-H, C 1′ ) = 4.2, 3 J(3-H, C 3′ ) = 2.9, 3 J(3-H, Me) = 6.1, 3 J(3-H, CO) = 4.6 Hz. Comparison of the vicinal coupling constants for compound XIVa with 3 J CH values found by us previously for substituted cyclopropanes [1,3] led us to conclude that the 3-H proton and the methyl group on C 2 are arranged at the same side of the cyclopropane ring plane. Among two carbonyl carbon atoms in the indandione fragment, the C 1′ atom [downfield signal, δ C 196.87 ppm, 3 J(3-H, C 1′ ) = 4.2 Hz] is oriented cis with respect to 3-H, whereas the C 3′ atom [upfield signal, δ C 194.14 ppm, 3 J(3-H, C 3' ) 2.9 Hz] is oriented trans.…”

“…We previously developed a procedure for the synthesis of spirocyclopropanes via reaction of 3-aryl-2-cyanoprop-2-enoic acid derivatives with zinc enolates derived from 2,2-dibromo-1,2,3,4-tetrahydronaphthalen-1-one and 2,2-dibromoindan-1-one [1]. In the present work we made an attempt to find out another synthetic approach to cyclopropane derivatives having one and two spiro carbon atoms.…”

Reactions of zinc enolates formed from 2,2-dibromoindan-1-one or 2,2-dibromo-3,4-dihydronaphthalen-1(2H)-one and zinc with alkyl 5,5-dimethyl-2-oxo-2,5-dihydrofuran-3-carboxylates

“…Reactions of derivatives of 3-aryl-2-cyanopropenoic acid with zinc enolates obtained from dibromotetralone or dibromoindanone and zinc are known to result in substituted spirocyclopropanes [1].…”

“…IR spectrum, ν, cm -1 : 1795, 1740, 1715. 1 Ethyl 3',4'-dihydro-4,4-dimethyl-1',2-dioxo-3-oxaspiro(bicyclo[3.1.0]heptan-6,2'-naphthalene)-1-carboxylate (V). To 1.5 g of fi ne zinc turnings in 8 ml of ether and 5 ml of ethyl acetate was added 0.013 mol of 2,2-dibromo-1-tetralone in 10 ml of ethyl acetate.…”

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Reactions of derivatives of 3-aryl-2-cyanopropenoic acid with zinc enolates obtained from dibromotetralone or dibromoindanone and zinc are known to result in substituted spirocyclopropanes [1].Boiling of alkyl 5,5-dimethyl-2-oxo-2,5-dihydrofuran-3-carboxylates Ia, Ib in a mixture ether-ethyl acetate for 40 min with zinc enolates II, III obtained by the reaction of 2,2-dibromoindan-1-one or 2,2-dibromo-3,4-dihydronaphthalen-1(2H)-one with zink afforded in good yields O Br Br OZnBr Br O Br Br OZnBr Br Zn Zn O O COOAlk H Me Me O H ZnBr Br O O Me Me COOAlk O O Me Me O H COOAlk _ ZnBr 2 n n Iа, Ib VIа, VIb, VII IVа, IVb, V II III II, III alkyl 4,4-dimethyl-2,1'-dioxo-3-oxaspiro[bicyclo[3.1.0] heptan-6,2'-indan]-1-carboxylates IVa, IVb and 4,4-dimethyl-2,1'-dioxo-3-oxaspiro(bicyclo[3.1.0]heptan-6,2'-tetralin)-1-carboxylate (V), whose structure was established by 1 H and 13 C NMR spectroscopy. The assignment of signals in the 1 H, 13 C NMR spectra was performed based on analysis of the data of 2D experiments HSQC, HMBC, NOESY.

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