Cyclopropanation of N-Substituted 2-Oxochromene- and 6-Bromo-2-oxochromene-3-carboxamides with Zinc Enolates Derived from 1-Aryl-2,2-dibromoalkanones

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 C^1a are arranged trans are formed by reactions of zinc enolates with the corresponding 2-oxochromene-3-carboxamides in the presence of hexamethylphosphoric triamide.__________Translated from Zhurnal Organicheskoi Khimii, Vol. 41, No. 4, 2005, pp. 539–546.Original Russian Text Copyright © 2005 by V. Shchepin, Silaichev, R. Shchepin, Ezhikova, Kodess.     

Reactions of Zinc Enolates Derived from 1-Aryl-2,2-dibromoalkanones with 3-Acetyl-6-bromochromen-2-one

Zinc enolates derived from substituted 1-aryl-2,2-dibromoalkanones react with 3-acetyl-6-bromochromen-2-one to give 1a-acetyl-1-alkyl-1-aroyl-6-bromo-1a,7b-dihydro-1H-cyclopropa[c]chromen-2-ones as a single stereoisomer.     

Reaction of Zinc Enolates Formed from 1-Aryl-2,2-dibromoalkanones and Zinc,with Substituted 2-Oxochromene-3-carbohydrazides

Zinc enolates formed from 1-aryl-2,2-dibromoalkanones and zinc react with N′-methyl-N′-phenyl- and N′-benzylidene-N-phenylhydrazides of 2-oxochromene-3-carboxylic acid to form the corresponding hydrazides of 1-alkyl-1-aroyl-2-oxo-1a,7b-dihydrocyclopropa[c]chromene-1a-carboxylic acid as a single geometric isomer.     

Reaction of Zinc Enolates Formed from 1-Aryl-2,2-dibromoalkanones and Zinc,with Aryl Esters and Chloride of 2-Oxo-2<Emphasis Type="Italic">H</Emphasis>-chromene-3-carboxylic Acid

Zinc enolates formed from 1-aryl-2,2-dibromoalkanones and zinc react with 2-oxo-2H-chromene-3-carboxylates to give aryl 1-alkyl-1-aroyl-2-oxo-1a,7b-dihydro-1H-cyclopropa[c]chromene-1a-carboxylates as a single geometric isomer. The reaction of the same zinc enolates with 2-oxo-2H-chromene-3-carboxyl chloride to form 2-bromo-1-arylalkenyl 1-alkyl-1-aroyl-2-oxo-1,7b-dihydro-1H-cyclopropa[c]chromene-1a-carboxylates.     

Reactions of Zinc Enolates of Substituted 1-Aryl-2,2-dibromobutanones with Alkyl Esters of 3-Oxo-3H-benzo[f]chromene-2-carboxylic Acid

Zinc enolates derived from substituted 1-aryl-2,2-dibromobutanones react with alkyl 3-oxo-3H-benzo[f]chromene-2-carboxylates to form alkyl 1-aroyl-1-ethyl-2-oxo-1,9c-dihydro-3-oxacyclopropa[c]phenanthrene-1a-carboxylate as a single geometric isomer.     

Reactions of 1-Aryl-2,2-dibromobutan-1-ones with Zinc and Alkyl 6-Bromo-2-oxo-2-H-chromen-3-carboxylate

Zinc enolates formed from 1-aryl-2,2-dibromobutan-1-ones and zinc react with alkyl 6-bromo-2-oxo-2-H-chromen-3-carboxylates affording alkyl 1-aroyl-6-bromo-2-oxo-1-ethyl-1,7b-dihydrocyclopropa[c]-chromen-1a(2H)-carboxylates as a single isomer.     

Cyclopropanation of 3-(2-Oxo-2<Emphasis Type="Italic">H</Emphasis>-chromen-3-yl-carbonyl)-2<Emphasis Type="Italic">H</Emphasis>-chromen-2-one with Zinc Enolates Derived from 1-Aryl-2,2-dibromoalkanones

Zinc enolates derived from 1-aryl-2,2-dibromoalkanones react with 3-(2-oxo-2H-chromen-3-ylcarbonyl)-2H-chromen-2-one to give 1-alkyl-1-aroyl-1a-(2-oxo-2H-chromen-3-ylcarbonyl)-1a, 7b-dihydrocyclopropa[c]-chromen-2(1H)-ones as a single stereoisomer.__________Translated from Zhurnal Organicheskoi Khimii, Vol. 41, No. 1, 2005, pp. 131–133.Original Russian Text Copyright © 2005 by Shchepin, Russkikh, Uzun, Silaichev.     

Reactions of Zinc Enolates Formed from 1-Aryl-2-bromo-2-phenylethanone or 2-Bromoindanone and Zinc,with Dimethyl 2-(1-Arylmethylene)malonates

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.     

Reaction of Zinc Enolates Derived from Substituted 2,2-Dibromobutyrophenones with Ethyl 5,5-Dimethyl-2-oxo-2,5-dihydrofuran-3-carboxylate

Zinc enolates derived from substituted 2,2-dibromobutyrophenones react with ethyl 5,5-dimethyl-2-oxo-2,5-dihydrofuran-3-carboxylate to give ethyl 6-aroyl-6-ethyl-4,4-dimethyl-2-oxo-3-oxabicyclo[3.1.0]-hexane-1-carboxylates mostly as a single geometric isomer.     

Reaction of Zinc Enolates of Alkyl Esters of Substituted 4-Bromo-3-Oxoalkanoic Acids with Aldehydes

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.     

Facile Synthesis of 6-Aryl-3-cyanopyridine-2-(1H)-thiones from Aryl Ketones

An improved synthesis of 6-aryl-3-cyanopyridine-2-(1H)-thiones utilizing enaminones as starting materials catalyzed by 1,4-diazabicyclo[2.2.2]octane (DABCO) was described. Moreover, a convenient one-pot conversion of aryl ketones to 6-aryl-3-cyanopyridine-2-(1H)-thiones was also developed in moderate to good yields (up to 80%).     

Reaction of Methyl 1-Bromocyclohexanecarboxylate with Zinc and 3-Aryl-1-(2-hydroxyphenyl)prop-2-en-1-ones

Russian Journal of Organic Chemistry - The reaction of 3-aryl-1-(2-hydroxyphenyl)prop-2-en-1-ones with methyl 1-bromocyclohexanecarboxylate and zinc resulted in the isolation, after hydrolysis of...     

Arylsulfonylaziridines and Arylsulfonylaminoethenes from N-(1-Aryl-2,2-dichloro-2-phenylethyl)arenesulfonamides

Russian Journal of Organic Chemistry -     

Nucleophilic Vinylic Substitutions of (E)- and (Z)-Ethyl 3-Aryl-3-chloro-2-cyanopropenoates with Primary and Secondary Amines

Some new (Z)-ethyl 3-amino-3-aryl-2-cyanopropenoates have been prepared in good yields by reacting (E)- and (Z)-ethyl 3-aryl-3-chloro-2-cyanopropenoates with primary and secondary amines. The (Z)-isomers were exclusively formed.although the starting material consisted of a mixture of (E)- and (Z)-isomers (≈ 1:1)     

Ni-Catalyzed Regioselective Hydroarylation of 1-Aryl-1,3-Butadienes with Aryl Halides

An efficient nickel-catalyzed regioselective hydroarylation of 1,3-dienes with aryl halides and a silane has been developed, affording a range of allylic arenes in good to excellent yields under mild conditions. This method exhibits broad substrate scope, and excellent functional group tolerance. Late-stage modification of complex architectures was demonstrated.     

Catalytic Cyclopropanation of Alkyl 2-Allyl-2-acetylaminomalonate and Methyl N-(Acetyl)(phenyl)dehydroalanine with Alkyl Diazoacetates

Cyclopropane analogs of aspartic and adipic acids were prepared by catalytic cyclopropanation of dehydro amino acid derivatives with alkyl diazoacetates in the presence of catalyst (dirhodium tetraacetate).     

Reaction of Alkyl 2-Bromoalkanoates with Zinc and Arylglyoxales

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.