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Bromine-containing organozinc compounds generated from 1,1-dibromo-3,3-dimethylbutan-2-one reacted with 2-arylmethylideneindan-1,3-diones and 5-arylmethylidene-2,2-dimethyl-1,3-dioxane-4,6-diones to give 3-aryl-2-(2,2-dimethylpropanoyl)spiro[cyclopropane-1,2′-indan]-1′,3′-diones and 1-aryl-6,6-dimethyl-2-(2,2-dimethylpropanoyl)-5,7-dioxaspiro[2.5]octan-4,8-diones, respectively. Reactions of 2-arylmethylideneindan-1,3-diones with bromine-containing zinc enolates derived from 1-aryl-2,2-dibromopropan-1-ones and 2,2-dibromo-1,2,3,4-tetrahydronaphthalen-1-one resulted in the formation of 2-aroyl-3-aryl-2-methylspiro-[cyclopropane-1,2′-indan]-1′,3′-diones and 2,3: 8,9-dibenzo-12-phenyldispiro[4.0.5.1]dodecane-1,4,7-trione, respectively.

Organozinc compounds formed from 1-aryl-2,2-dibromoalkanes, α,α-dibromopinacoline, and dialkyl dibromomalonates and zinc react with (3-phenylprop-2-enylidene)malonodinitriles and primary amides of 2-cyano-5-phenylpenta-2,4-dienoic acid to form 2-alkyl-2-aroyl-3-(phenylvinyl)cyclopropan-1,1-dicarboxylic acid dinitriles, N-substituted amides of 3-(phenylvinyl)-2-(2,2-dimethylpropanoyl)-1-cyanocyclopropan-1-carboxylic acids, and alkyl 3-R-6-(phenylvinyl)-2,4-dioxo-5-cyano-3-azabicyclo[3.1.0]-hexan-1-carboxylates as a single stereoisomer.

Methyl 1-(2-bromo-2-methyl-1-oxopropyl)-, 1-(1-bromocyclopentylcarbonyl)-, and 1-(1-bromocyclohexylcarbonyl) cyclobutanecarboxylates reacted with zinc and aromatic aldehydes to give, respectively, 7-aryl-2,2-dimethyl-6-oxaspiro[3.5]nonane-5,9-diones, 11-aryl-12-oxadispiro[3.1.4.3]tridecane-5,13-diones, and 12-aryl-13-oxadispiro[3.1.5.3]tetradecane-5,14-diones.

Zinc enolates generated from dimethyl 4-bromo-2,2-dimethyl-3-oxohexane-1,6-dioate and zinc reacted with aromatic aldehydes giving methyl 2,2-dimethyl-3-oxo-3-(5-oxo-2-aryltetrahydrofuran-3-yl)propanoates. The reaction of zinc enolates obtained from dimethyl 4-bromo-2,2-dimethyl-3-oxoheptane-1,7-dioate and zinc with aromatic aldehydes depending on the synthesis conditions led to the formation either methyl 2,2-dimethyl-3-oxo-3-(6-oxo-2-aryltetrahydropyran-3-yl)propanoates or 3-(5,5-dimethyl-4,6-dioxo-2-aryltetrahydropyran-3-yl)propanoates. The compounds synthesized formed as a single diastereomer of E-configuration.

Zinc enolates obtained from 2,2-dibromonidan-1-one or 2,2-dibromo-1-tetralone and zinc reacted with alkyl esters and amides of 2-oxochromen-3-carboxylic acid giving the corresponding derivatives of 2,1′-dioxo-spiro(1a,7b-dihydrocyclopropa[c]chromen-1,2′-indan)-or 1′,2′,3′,4′-tetrahydro-2,1′-dioxospiro(1a,7b-dihydrocyclopropa[c]chromen-1,2′-naphthalene)-1a-carboxylic acids prevailingly in the form of a single geometric isomer.

Zinc enolates derived from 2,2-dibromoindan-1-one and 2,2-dibromo-1,2,3,4-tetrahydronaphthalen-1-one reacted with 2-arylmethylidenemalononitriles, alkyl 3-aryl-2-cyanoprop-2-enoates, and N-substituted 3-aryl-2-cyanoprop-2-enamides to give, respectively, 3-aryl-1′-oxo-1′,3′-dihydrospiro[cyclopropane-1,2′-indene]-2-2-dicarbonitriles, 3-aryl-1′-oxo-3′,4′-dihydro-1′H-spiro[cyclopropane-1,2′-naphthalene]-2,2-dicarbonitriles, alkyl 3-aryl-2-cyano-1′-oxo-1′,3′-dihydrospiro[cyclopropane-1,2′-indene]-2-carboxylates, alkyl 3-aryl-2-cyano-1′-oxo-3′,4′-dihydro-1′H-spiro[cyclopropane-1,2′-naphthalene]-2-carboxylates, and N-substituted 3-aryl-2-cyanol-1′-oxo-3′,4′-dihydro-1′H-spiro[cyclopropane-1,2′-naphthalene]-2-carboxamides as a single diastereoisomer. The stereoconfiguration of the products was determined by 1H and 13C NMR spectroscopy.

Organozinc compounds prepared from bromomalonic acid esters and zinc react with 3-aryl-2-cyanopropenoic acid primary amides giving a single diastereomer of the corresponding 1-R′-4-aryl-2,6-dioxo-5-cyanopiperidine-3-carboxylic acid esters, or 3-R′-6-aryl-2,4-dioxo-5-cyano-3-azabicyclo[3.1.0]hexene-1-carboxylic acid esters.

Organozinc compounds obtained from 1-aryl-2-bromo-2-methylpropanone and zinc react with N-benzyl-3-aryl-2-cyanoacrylamides or N-[6-(2-cyano-1-oxo-3-phenylprop-2-enylamino)hexyl]-2-cyano-3-phenylacrylamide to give 4,6-diaryl-1-benzyl-6-hydroxy-5,5-dimethyl-2-oxopiperidine-3-carbonitriles or 1,6-bis(6-aryl-3-cyano-6-hydroxy-5,5-dimethyl-2-oxo-4-phenylpiperidyl)hexanes as a single isomer with trans-located piperidine hydrogen atoms.

Reformatsky reagents obtained from methyl 1-bromocyclohexane-and 1-bromocyclopentane-1-carboxylates reacted with aromatic aldehyde phenyl-and benzoylhydrazones to give 3-aryl-2-phenylamino-2-azaspiro[3.5]nonan-, 3-aryl-2-phenylamino-2-azaspiro[3.4]octan-, 3-aryl-2-benzoylamino-2-azaspiro[3.5]-nonan-, and 3-aryl-2-benzoylamino-2-azaspiro[3.4]octan-1-ones, respectively. The reaction of furan-2-carbaldehyde phenylhydrazone with methyl 1-bromocyclohexane-1-carboxylate and zinc led to the formation of 4-(2-furyl)-2-phenyl-2,3-diazaspiro[4.5]decan-1-one.

3-Aroyl-6-bromochromen-2-ones and 2-benzoylbenzo[f]chromen-3-one reacted with zinc enolates derived from 1-aryl-2-bromoalkanones and 1-aryl-2-bromo-2-phenylethanone to give, respectively, 4-(1-alkyl-2-aryl-2-oxoethyl)-3-aroyl-6-bromochroman-2-ones and 1-(2-aroyl-1-methyl-2-oxoethyl)-2-benzoyl-1,2-dihydrobenzo[f]chromen-3-ones as a single stereoisomer. Treatment with acetic anhydride of the intermediate product obtained from 3-benzoyl-6-bromochromen-2-one and [1-(4-chlorophenyl)-2-phenylethen-1-yloxy]-zinc(II) bromide resulted in the formation of 3-(1-acetoxy-1-phenylmethylidene)-6-bromo-4-[2-(4-chlorophenyl)-2-oxo-1-phenylethyl]chroman-2-one.

Alkyl 5,5-dimethyl-2-oxo-2,5-dihydrofuran-3-carboxylates react with zinc enolates prepared from 1-aryl-2-bromo-2-phenylethanones, 2-bromo indanone, 2-bromo-6-methyltetralone and zinc with formation of ethyl 4-(2-aryl-2-oxo-1-phenyl-ethyl)-5,5-dimethyl-2-oxotetrahydrofuran-3-carboxylates, alkyl 5,5-dimethyl-2-oxo-4-(1-oxoindan-2-yl)tetrahydrofuran-3-carboxylates, and ethyl 5,5-dimethyl-4-(6-methyl-1-oxo-1,2,3,4-tetrahydronaphthalen-2-yl)-2-oxotetrahydrofuran-3-carboxylates respectively, mainly as single diastereomers.

Zinc enolates obtained from ethyl 2,2-dialkyl-4,4-dibromo-3-oxobutanoates and zinc react with N-substituted 2-oxochromen-3-carboxamides forming ethyl 3-{1a-(R3-carbamoyl)-2-oxo-1a,7b-dihydrocyclopropa[c]chromen-1-yl}-2,2-dialkyl-3-oxopropanoate isomer with a Z-position of methine hydrogens. Zinc enolates prepared from alkyl 2,2-dialkyl-4,4-dibromo-3-oxopentanoates and-hexanoates and zinc react with N-substituted 2-oxochromen-3-carboxamides to give rise to esters of 3-{1-alkyl-1a-(R3-carbamoyl)-2-oxo-1a,7b-dihydrocyclopropa-[c]chromen-1-yl}-2,2-dialkyl-3-oxopropanoic acid as isomers with the E-position of the methine proton and the alkyl substituent. The reaction carried out in the presence of small quantities of THF and HMPA leads to the formation of 9c-alkyl-2-R3-9b,9c-dihydro-5-oxa-2-azacyclopenta[2,3]-cyclopropa[1,2-a]naphthalene-1,3,4-triones. Zinc enolates from alkyl 2,2-dialkyl-4,4-dibromo-3-oxopentanoates and-hexanoates and zinc with the secondary amides of 2-oxochromen-3-carboxylic acid form alkyl 3-{2-oxo-1a-(piperidinocarbonyl)-and 3-{6-R1-1a-(morpholinocarbonyl)-2-oxo-1a,7b-dihydrocyclopropa[c]chromen-1-yl}-2,2-R2,R2-3-oxopropanoates as single geometrical isomers.

Zinc enolates derived from 1-R-2,2-dibromoethanone reacted with 3-(2-oxo-4a,8a-dihydro-2H-chromene-3-carbonyl)chromen-2-one to give the corresponding 1-R-1a-{(1-R-2-oxo-1,7b-dihydrocyclopropa[c]chromen-1(2H)-yl)carbonyl}-1a,7b-dihydrocyclopropa[c]chromen-2(1H]-ones as a single diastereoisomer with cis arrangement of the hydrogen atoms with respect to the cyclopropane ring plane. Reactions of the same electrophilic substrate with zinc enolates obtained from 1-aryl-2,2-dibromoalkanones led to the formation of 1-alkyl-1a-{(1-alkyl-1-aroyl-2-oxo-1,7b-dihydrocyclopropa[c]chromen-1(2H)-yl)carbonyl}-1-aroyl-1a,7b-dihydrocyclopropa[c]chromen-2(1H)-ones as a single diastereoisomer with trans arrangement of the alkyl group and hydrogen atom with respect to the cyclopropane ring plane.

Reformatsky reagent generated from methyl 1-bromocyclohexane-1-carboxylate reacted with N-aryl-2-oxochromene-3-carboxamides and N-aryl-6-bromo-2-oxochromene-3-carboxamides to give, depending on the conditions, the corresponding N-aryl-(6-bromo)-4-(1-methoxycarbonylcyclohexyl)-2-oxochroman-3-carboxamides or 3-aryl-(9-bromo)-1,1-pentamethylene-2,3,4,4a,5,10b-hexahydro-1H-chromeno[3,4-c]pyridine-2,4,5-triones. The products were isolated as a single diastereoisomer.

Organozinc compounds obtained by treatment of dialkyl 2,2-dibromomalonates with zinc reacted with N-substituted 2-oxochromene-3-carboxamides to give dialkyl 1a-R-carbamoyl-2-oxo-1a,7b-dihydro-2H-cyclopropa[c]chromene-1,1-dicarboxylates or alkyl 2-R-1,3,4-trioxo-2,3-dihydro-1H,9bH-chromeno[3′,4′:1,3]-cyclopropa[1,2-c]pyrrole-9c-carboxylates. Reactions of N-substituted 2-oxochromene-3-carboxamides with zinc enolates derived from methyl 4,4-dibromo-3-oxoalkanoates led to the formation of the corresponding 9c-alkyl-2-R-2,3-dihydrochromeno[3′,4′:1,3]cyclopropa[1,2-c]pyrrole-1,3,4-triones.

Zinc enolate derived from 1,1-dibromo-3,3-dimethylbutan-2-one reacts with 3-aryl-2-cyanoprop-2-enamides and aryl 3-aryl-2-cyanoprop-2-enoates to give the corresponding derivatives of 3-aryl-2-(2,2-dimethylpropanoyl)-1-cyanocyclopropane-1-carboxylic acid as a single stereoisomer with cis arrangement of the hydrogen atoms at the cyclopropane ring. The reactions of the same zinc enolate with 3-morpholinocarbonyl-2H-chromen-2-one and 2-morpholinocarbonyl-3H-benzo[f]chromen-3-one lead to formation of 1-(2,2-dimethylpropanoyl)-1a-morpholinocarbonyl-1a,7b-dihydrocyclopropa[c]chromen-2-one and 1-(2,2-dimethylpropanoyl)-1a-morpholinocarbonyl-1a,9c-dihydrobenzo[f]cyclopropa[c]chromen-2-one, respectively as a single stereoisomer.

Zinc enolates derived from 1-aryl-2-bromo-2-phenylethanone react with alkyl 2-oxochromene-3-carboxylates and methyl 6-bromo-2-oxochromene-3-carboxylate to give, respectively, alkyl 4-(2-aryl-2-oxo-1-phenylethyl)-2-oxochroman-3-carboxylates and methyl 6-bromo-4-(2-aryl-2-oxo-1-phenylethyl)-2-oxochroman-3-carboxylate as a single stereoisomer. Zinc enolates derived from 2-bromoindan-1-one react with alkyl 2-oxochromene-3-carboxylates to give alkyl 2-oxo-4-(1-oxoindan-2-yl)chroman-3-carboxylates as a single stereoisomer.

Zinc enolates formed from 1-aryl-2-bromo-2-phenylethanones and zinc react with dimethyl 2-(1-arylmethylene)malonates to afford dimethyl 2-(1,3-diaryl-3-oxo-2-phenylpropyl)malonates. The latter react with cyclohexylamine, piperidine, or morpholine to give the corresponding monosubstituted amides. The zinc enolate derived from 2-bromoindanone and zinc reacts with dimethyl 2-(4-bromobenzylidene)malonate, yielding dimethyl 2-[(4-bromophenyl)(1-oxoindan-2-yl)methyl]malonate. The final products largely form as a single diastereomer.

Ethyl esters of 2,4-dibromo-2-R1-4-R2-3-oxopentanoic and -hexanoic acids react with zinc and aliphatic or aromatic aldehydes under the conditions of the Reformatskii reaction to give 3-R1-5,5-R2, R2-6-R3-2,3,5,6-tetrahydropyran-2,4-diones, which are obtained in three forms: keto, enol with enolization of the keto group, and enol with enolization of the ester group. The keto form is isolated by crystallization from a mixture of CCl4 and petroleum ether; the first enol form, from MeOH, EtOH, and polar aprotic solvents; and the second enol form, from CHCl3. The second enol form is oxidized in DMSO to form a keto compound containing a hydroxy group at the 3-position of the heteroring.

Reformatsky reagent obtained by treatment of methyl α-bromoisobutyrate with zinc reacts with dimethyl 2-arylmethylidenemalonates to give trimethyl 2-aryl-3-methylbutane-1,1,3-tricarboxylates. The reaction of the same compound with ethyl 3-aryl-2-(4-methylphenylcarbamoyl)acrylates yields cyclic products, ethyl 4-aryl-5,5-dimethyl-1-(4-methylphenyl)-2,6-dioxopiperidine-3-carboxylates. Treatment of the latter with morpholine and phenylhydrazine leads to the corresponding 4-aryl-5,5-dimethyl-1-(4-methylphenyl)-2,6-dioxopiperidine-3-carboxylic acid morpholides and phenylhydrazides. The products are formed as a single diastereoisomer.

Zinc enolates generated from 1-aryl-2-bromoalkanones and zinc react with dimethyl 2-(1-arylmethylene)malonate to form dimethyl 2-(2-alkyl-1,3-diaryl-3-oxopropyl)malonates. The latter react with benzylamine or cyclohexylamine to form the corresponding disubstituted amides, while the reactions with piperidine, morpholine, and p-methoxyaniline provide monosubstituted amides of the corresponding target derivatives.

Zinc enolates derived from 1-aryl-2,2-dibromoalkanones react with N-cyclohexyl-2-oxochromene-3-carboxamides to give N-cyclohexyl-1-alkyl-1-aroyl-2-oxo-1a,7b-dihydrocyclopropa[c]chromene-1a-carboxamides mainly as cis isomers with respect to the substituents in positions 1 and 1a. Reactions of the same zinc enolates with N-benzyl-2-oxochromene-3-carboxamide and N-benzyl-6-bromo-2-oxochromene-3-carboxamide lead to formation of 1-aryl-2-benzyl- and 1-aryl-2-benzyl-6-bromo-1-hydroxy-9c-alkyl-1,2,9b,9c-tetrahydro-5-oxa-2-azacyclopenta[2,3]cyclopropa[1,2-a]naphthalene-3,4-diones. The reaction of zinc enolates with N-aryl-2-oxochromene-3-carboxamides in a weakly polar solvent (diethyl ether or ethyl acetate) affords mixtures of cis-N-aryl-1-aroyl-1-alkyl-2-oxo-1a,7b-dihydrocyclopropa[c]chromene-1a-carboxamides and their cyclic isomers, 9c-alkyl-1,2-diaryl-1-hydroxy-1,2,9b,9c-tetrahydro-5-oxa-2-azacyclopenta[2,3]cyclopropa[1,2-a]naphthalene-3,4-diones, the latter prevailing. N-Substituted 1-alkyl-1-aroyl-2-oxo-1a,7b-dihydrocyclopropa[c]chromene-1a-carboxamides in which the aroyl group on C1 and the carboxamide group on C1a are arranged trans are formed by reactions of zinc enolates with the corresponding 2-oxochromene-3-carboxamides in the presence of hexamethylphosphoric triamide.

The Reformatskii reagents formed from alkyl esters of α-bromoacetic, α-bromopropanoic, and α-bromoisobutyric acids and zinc react with N-arylamides of 2-oxochromene-3-carboxylic acid, yielding 3-R1-1-R2-1-R3-4a,10b-dihydro-1H-chromeno[3,4-c]pyridine-2,4,5-triones.

Zinc enolates formed from 1-aryl-2-bromoalkanones react with methyl esters of substituted 2-oxochromene-3-carboxylic acids to give methyl esters of 6-bromo- or 6,8-dibromo-4-(2-aryl-2-oxo-1-R- ethyl)-2-oxochromane-3-carboxylic acids as mixtures of two diastereomers.

Methyl esters of 1-(1-bromocyclopentylcarbonyl)- and 1-(1-bromocyclohexylcarbonyl)cyclopentanecarboxylic or 1-(1-bromocyclopentylcarbonyl)cyclohexanecarboxylic acids react with zinc and aromatic aldehydes to form 14-aryl-13-oxadispiro[4.1.4.3]tetradecane-6,12-diones, 13-aryl-14-oxadispiro[4.1.5.3]pentadecane-6,15-diones, and 15-aryl-14-oxadispiro[4.1.5.3]pentadecane-6,13-diones, respectively.

Zinc enolates of 3-alkyl-6-aryl-5,5-dimethyl-2,3,5,6-tetrahydropyrane-2,4-diones react with acyl chlorides to form O-acylation products, 4-acyloxy-3-alkyl-6-aryl-5,5-dimethyl-5,6-dihydropyrane-2-ones. Sodium enolates of these pyranediones react in DMSO with substituted benzyl bromides to give mainly C-alkylation products, 3-alkyl-6-aryl-3-(4-R-benzyl)-5,5-dimethyl-2,3,5,6-tetrahydropyrane-2,4-diones, as single geometric isomers. In some cases, O-alkylation products, 4-alkoxy-3-alkyl-6-aryl-5,5-dimethyl-5,6-dihydropyrane-2-ones, are formed as by-products (∼10-15%).

Zinc enolates formed from ethyl 4-bromo-2,2,4-trimethyl-3-oxopentanoate react under the conditions of one- of two-stage synthesis with aliphatic, unsaturated, or aromatic aldehydes to form 6-R-2,2,4,4-tetramethyl-2,3,5,6-tetrahydropyran-2,4-diones. Zinc enolates obtained from ethyl 4-bromo-2,2-dimethyl-3-oxopentanoate, -hexanoate, and -2,2,5-trimethyl-3-oxohexanoate under the similar conditions react with aliphatic or aromatic aldehydes to give mainly 5-R1-6-R2-3,3-dimethyl-2,3,5,6-tetrahydropyran-2,4-diones as E or Z isomers or their mixtures. Zinc enolates generated from the ethyl 4-bromo-2,2-diethyl- or 2-benzyl-2-ethyl-3-oxobutanoates react with aromatic aldehydes to give ethyl 5-R-2-R-2-ethyl-3-oxo-4-pentenoates as E isomers.

1-Aryl-2,2-dibromobutan-1-ones react with zinc and dialkyl arylmethylene- or isobutylidenemalonates to give dialkyl 2-aroyl-3-phenyl(isopropyl)-2-ethylcyclopropane-1,1-dicarboxylates which are formed mainly as Z isomers.

Reformatsky reagents derived from methyl 1-bromocyclobutane- and 1-bromocycloheptanecarboxylates reacted with Schiff bases to give 2,3-diaryl-2-azaspiro[3.3]heptane-1-ones and 2,3-diaryl-2-azaspiro-[3.6]decan-1-ones, respectively.

Reformatsky reagent prepared from methyl 1-bromocyclopentanecarboxylate and zinc reacted with 2-oxochromen-and 6-bromo-2-oxochromen-3-carboxylic acids N-arylamides yielding 3-aryl-1,1-tetramethylene-and 3-aryl-9-bromo-1,1-tetramethylene-2,3,4,4a,5,10b-hexahydro-1H-chromeno[3,4-c]pyridine-2,4,5-triones as single diastereomers.

Zinc enolates derived from 1-aryl-2,2-dibromoalkanones reacted with tetramethyl 2,2′-(1,4-phenylenedimethylidene)dimalonate, dimethyl 3,3′-(1,4-phenylene)bis(2-cyanoacrylate), and 2,2′-(1,4-phenylenedimethylidene)bis(malononitrile) to give, respectively, tetramethyl 3,3′-(1,4-phenylene)bis(2-alkyl-2-aroylcyclopropane-1,1-dicarboxylates), dimethyl 3,3′-(1,4-phenylene)bis(2-alkyl-2-aroyl-1-cyanocyclopropane-1-carboxylates), and 3,3′-(1,4-phenylene)bis(2-alkyl-2-aroylcyclopropane-1,1-dicarbonitriles) as a single stereoisomer.

Organozinc compounds, obtained from dibromomalonic acid dialkyl esters and zinc, react with 2-arylmethylmalonic acid dinitriles and 3-aryl-2-cyanopropenoic acid methyl esters forming 3-aryl-2,2-dicyanocyclopropane-1,1-dicarboxylic acid dialkyl esters and 3-aryl-2-cyanocyclopropane-1,1,2-tricarboxylic acid trimethyl esters. 1H and 13C NMR, 3JCH constants are considered.

Zinc enolates derived from 1-aryl-2,2-dibromoalkan-1-ones react with 2-arylmethylidenemalononitriles to give 2-alkyl-3-aryl-2-aroylcyclopropane-1,1-dicarbonitriles.

Organozinc compounds obtained by treatment of dialkyl 2,2-dibromomalonates with metallic zinc reacted with N-substituted 3-aryl-2-cyanoprop-2-enoic acid amides to give alkyl 3-R-6-aryl-5-cyano-2,4-dioxo-3-azabicyclo[3.1.0]hexane-1-carboxamides as a single stereoisomer.

Zinc enolates prepared from 1-aryl-2,2-dibromoalkanones and zinc react with alkyl and aryl 3-aryl-2-cyanopropenoates affording alkyl and aryl 2-alkyl-3-aryl-2-aroyl-1-cyanocyclopropane-1-carboxylates.

Zinc enolates obtained from methyl 4-bromo-2,2-dimethyl-3-oxo-4-phenylbutanoates and zinc react with aromatic aldehydes to form 6-aryl-3,3-dimethyl-5-phenyl-2,3,5,6-tetrahydropyran-2,4-diones as a single geometric isomer.

Zinc enolate obtained from 1,1-dibromo-3,3-dimethylbutan-2-one reacted with N-substituted 2-oxochromene-3-carboxamides and 3-oxobenzo[f]chromene-2-carboxamides affording 1-(2,2-dimethyl-propanoyl)-2-oxo-1a, 7b-dihydrocyclopropa[c]chromene-1a-carboxamides and 1-(2,2-dimethylpropanoyl)-2-oxo-1a, 9C-dihydrobenzo[f]cyclopropa[c]chromene-1a-carboxamide as single isomers.

Reformatsky reagents prepared from methyl 1-bromocycloalkanoates and zinc react with azomethines or azines to give 2,3-diaryl-2-azaspiro[3.5]nonan-1-ones, 2,3-diaryl-2-azaspiro[3.4]octan-1-ones or 2,2′ -bis(3-aryl-1-oxo-2-azaspiro[3.5]nonanes), respectively.

Zinc enolates derived from ethyl 4-bromo-2,2,4-trimethyl-3-oxopentanoate and 4-bromo-4- ethyl-2,2-dimethyl-3-oxohexanoate react with 2-furan-, 2-thiophene-, 1-(3-nitrophenyl)-2-pyrrole-, 1-acyl-3-indole-, and 2-pyridinecarbaldehydes to give the corresponding 6-hetaryl-5,5-dialkyl-3,3-dimethyltetrahydropyran-2,4-diones.

Reformatsky reagents generated from alkyl esters of bromoacetic, α-bromopropionic, α-bromobutyric, and α-bromoisobutyric acids react with alkyl esters of 6,8-dibromo-2-oxochromene-3-carboxylic acid to form alkyl esters of 6,8-dibromo-4-(1-alkoxycarbonylalkyl)-2-oxochromane-3-carboxylic acid.

Reformatsky reaction of methyl α-bromoisobutyrate with Schiff bases derived from salicylaldehyde and its analogs gives the corresponding 1,4-disubstituted 3,3-dimethylazetidin-2-ones.

Reformatsky reactions of ethyl α-bromopropionate, methyl α-bromobutyrate, and methyl α-bromo-isobutyrate with N-substituted 6-bromo-2-oxochromene-3-carboxamides in the system diethyl ether–benzene– HMPA give N-benzyl-6-bromo-4-(1-alkoxycarbonylalkyl)-2-oxochroman-3-carboxamides, while in the system diethyl ether–benzene–HMPA–THF, 3-R1-1-R2-1-R3-9-bromo-2,3,4,4a,5,10b-hexahydro-1H-chromeno[3,4-c]-pyridine-2,4,5-triones are obtained.

Methyl 1-(2-bromoisobutyryl)cyclopentanecarboxylate and 3-(1-bromocyclopentyl)-2,2-dimethyl-3-oxopropionate react with zinc and aromatic aldehydes to afford 8-aryl-9,9-dimethyl-7-oxaspiro[4.5]decane-6,10-diones and 10-aryl-7,7-dimethyl-9-oxaspiro[4.5]decane-6,8-diones, respectively.

Reformatsky reagent derived from methyl α-bromoisobutyrate reacts with methyl and ethyl 2-oxo-2H-benzo[f]chromene-3-carboxylates and N-benzyl-2-oxo-2H-benzo[f]chromene-3-carboxamide to afford the corresponding derivatives of 4-(1-methyl-1-methoxycarbonylethyl)-2-oxo-3,4-dihydro-2H-benzo[f]chromene-3-carboxylic acid as a single stereoisomer.

Methyl esters of 1-(α-bromoisobutyryl)cyclohexanecarboxylic or 3-(1-bromocyclohexyl)-2,2-dimethyl-3-oxopropanoic acids react with zinc and arylglyoxals to form 3-aroyl-4,4-dimethyl-2-oxaspiro[5.5]undecane-1,5-diones or 1-aroyl-4,4-dimethyl-2-oxaspiro[5.5]undecane-3,5-diones, respectively. The former products react with phenylhydrazine, yielding 3-[aryl(2-phenylhydrazono)methyl]-4,4-dimethyl-2-oxaspiro[5.5]undecane-1,5-diones.

Methyl 2-bromo-2-methylpropionate reacts with zinc and arylglyoxals under conditions of Reformatsky reaction in ether-HMPA mixture to afford 1-aryl-4,4,8,8-tetramethyl-2,6-dioxabicyclo[3.3.0]octane-3,7-diones in 68-85% yield. Methyl 2-bromopropionate reacts with zinc and 4-bromophenylglyoxal in the same way giving the bicyclic product in 28% yield. The bromination of 1-(4-tolyl)-4,4,8,8-tetramethyl-2,6-dioxabicyclo[3.3.0]octane-3,7-dione with bromosuccinimide results in successive replacement of hydrogens in the tolyl moiety by bromine. The calculation of formation enthalpy for stereoisomers of compounds obtained in AM1 approximation predicts the highest stability for chair-type conformation with eclipsed position of substituents at C1 and C5 atoms.

Methyl 4-bromo-3-oxo-2,2,4-trimethylpentanoate reacts with zinc and arylglyoxals yielding 6-aroyl-3,3,5,5-tetramethyl-2,3,5,6-tetrahydropyran-2,4-diones. The latter with phenylhydrazine afford 6-(1-aryl-2-phenylhydrazonomethyl)-3,3,5,5-tetramethyl-2,3,5,6-tetrahydropyran-2,4-diones.