Regio- and stereoselective synthesis of tetrahydroindolysines,tetrahydropyridin-6-olates,and cyclopropanes from pyridinium ylides and unsaturated nitriles

The regio- and stereoselectivity of the reactions of pyridinium ylides with unsaturated nitriles are dependent on the electronic nature of the substituent in position 3 of the pyridine ring. The reaction of 1-carbamoylmethylide-3-cyanopyridinium with arylmethylenemalononitriles or arylmethylcyanoacetic esters proceeds regio- and stereoselectively with the formation of substituted 2-aryl-3-carbamoyl-6-cyano-2,3-trans- or 2,3-cis-1,2,3,8a-tetrahydroindolysines. The condensation of pyridinium 1-carbamoylmethylide with arylmethylenecyanoacetic ether leads to 4-aryl-2-oxo-3-(1-pyridinio)-5-cyano-3,4-trans-1,2,3,4-tetrahydropyridin-6-olates. The reaction of pyridinium (3-methylpyridinium) 1-carbamoylmethylide with arylmethylenemalononitriles results in the formation of 2-aryl-1,1-dicyano-3-carbamoyl-3-(1-pyridinio)- or (3-methyl-1-pyridinio)-1-propanides, which undergo stereoselective 1,3-transelimination with the formation of 3-aryl-1,1-dicyano-2-carbamoylcyclopropanes.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 1, pp. 146–155. January, 1991.     

Reactions of lithiated (E)-3-halo-1-phenylsulfonylprop-1-enes and (Z)-1-halo-3-phenylsulfonylprop-1-enes with aldehydes

(E)-3-Chloro-1-phenylsulfonylprop-1-ene and its iodo- and bromo-analogues, (Z)-1-iodo-3-phenylsulfonylprop-1-ene and (Z)-1-bromo-3-phenylsulfonylprop-1-ene, have each been successfully converted into lithiated carbanions which react regioselectively with aromatic aldehydes to give gamma-alkylated products whose nature depends upon the halogen substituent: the chloro-sulfones yield (2Z)-1-aryl-2-chloro-4-phenylsulfonylbut-2-en-1-ols but the bromo- and iodo-derivatives behave differently, yielding (1E)-trans-4-aryl-3,4-epoxy-1-phenylsulfonylbut-1-enes. In sharp contrast, the same lithiated sulfones react with aliphatic aldehydes to give anti-configured beta-hydroxysulfones which are formed via diastereoselective alpha-alkylation reactions.     

Stereoselective transformation of 1,3-dithia-4-cyclohexene enaminonitriles into substituted 3,4-trans-1,2,3,4-tetrahydropyridine-6-thiolates with pyridinium ylides

4-Amino-6-aryl-2,2-dialkyl-5-cyano-1,3-dithia-4-cyclohexenes react with pyridinium ylides in thermodynamically controlled conditions with the formation of 4-aryl-2-oxo-thioxo)-3-(1-pyridino)-5-cyano-3,4-trans-1,2,3,4-tetrahydropyridine-6-thiolates. Arylidenecyanothioacetamides act as intermediates of this recyclization, and the corresponding pyridine-6-thiolates were obtained from them by an independent method. The synthesized hydrogenated pyridine-6-thiolates are in the half-chair conformation with a trans-diaxial position of the 3-H and 4-H hydrogen atoms.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1082–1086, August, 1991.     

Diaziridine ring expansion in 6-aryl-1,5-diazabicyclo[3.1.0]hexanes upon reactions with activated olefins in ionic liquids

Reactions of 1,3-diphenylpropen-2-one and α-nitrostyrenes with azomethine imines, generated from 6-aryl-1,5-diazabicyclo[3.1.0]hexanes on catalysis with Et2O•BF3 in ionic liquids, were found to proceed with high regio- and stereoselectivity to afford the products of the diaziridine ring expansion, viz., [3-aryl-2-phenyltetrahydro-1H,5H-pyrazolo[1,2-a]pyrazol- 1-yl](phenyl)methanones, 1,3-diaryl-2-nitrotetrahydro-1H,5H-pyrazolo[1,2-a]pyrazoles and 5-aryl-6-(3-nitrophenyl)-2,3-dihydro-1H-pyrazolo[1,2-a]pyrazolium tetrafluoroborates (hexafluorophosphates). The reactions discovered are new, more simple methods for the syn- thesis of bicyclic structures.     

Synthesis of 3,4-dihydro-2H-pyrans by hetero-Diels-Alder reactions of functionalized alpha,beta-unsaturated carbonyl compounds with N-vinyl-2-oxazolidinone

Cycloadditions of 3-aryl-2-benzoyl-2-propenenitriles and 3-phenylsulfonyl-3-buten-2-one to N-vinyl-2-oxazolidinone proceed regio- and diastereoselectively yielding cis and trans diastereoisomers of 4-aryl-3,4-dihydro-2-(2-oxo-3-oxazolidinyl)-2H-pyrans in 37-65% yield. Cycloadducts cis- were the major products. Reaction of 5-arylidene-1,3-dimethylbarbituric acids with dienophile afforded mixtures of 2H-pyrano[2,3-d]pyrimidine-2,4(3H)-diones trans and products resulted from an elimination of 2-oxazolidinone, in 50-52% yield. To confirm the experimental results, semiempirical AM1 and PM3 calculations of frontier orbital energies have been performed.     

Unexpected high regiocontrol in Heck reaction of fluorine-containing electron-deficient olefins—Highly regio- and stereoselective synthesis of β-fluoroalkyl-α-aryl-α,β-unsaturated ketones

Treatment of (E)-4,4,4-trifluoro-1-aryl-2-buten-1-one with various aryldiazonium salts in the presence of palladium catalyst gave the corresponding α-arylated Heck adducts with high regio- and stereoselectivity in good to high yields.     

Investigation of the stereochemistry of the [3.3]-sigmatropic rearrangement of the sp-isomer of 2-allylthio-5-acetyl-6-methyl-4-(2-nitrophenyl)-3-cyano-1,4-dihydropyridine

The reaction of the syn-periplanar conformer (the sp-isomer) of morpholinium 5-acetyl-6-methyl-4-(2-nitrophenyl)-3-cyano-1,4-dihydropyridine-2-thiolate with allyl bromide proceeds regio- and stereoselectively with the formation of the sp-isomer of the substituted 2-allylthio-1,4-dihydropyridine. The [3.3]-sigmatropic rearrangement of the last leads to the sp-isomer of 3,4-trans-3-allyl-5-acetyl-6-methyl-4-(2-nitrophenyl)-3-cyano-1,2,3,4-tetrahydropyridine-2(1H)-thione.Deceased.A. N. Nesmeyanov Institute of Hetero-organic Compounds, Russian Academy of Sciences (RAN), Moscow 117813. N. D. Zelinskii Institute of Organic Chemistry, RAN, Moscow 117913. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 643–652, May, 1997.     

Regio- and stereoselective synthesis of 1-aryl-1-thio-2-thiophosphinylethene derivatives via a radical process

Radical additions of S-thiophosphinyl dithiocarbonate to terminal aromatic alkynes afford (E)-1-aryl-1-thio-2-thiophosphinylethene derivatives regio- and stereoselectively in high yields. The transformations of the products are also described.     

3H-Pyrroles as a platform for the catalyst-free construction of dihydropyrrolo[2,1-b]oxazoles: [4 + 2]-cycloaddition vs [2 + 3]-annulation with 1-cyano-3-hydroxyalkynes

Non-aromatic pyrrole isomers, 3,3-dialkyl-2-aryl-3H-pyrroles, were reacted with 1-cyano-3-hydroxyalkynes under mild, catalyst-free conditions (20–60?°C) to regio- and stereoselectively afford (Z)-2-(dihydropyrrolo[2,1-b]oxazolylidene)acetonitriles in 62–82% yield, thus evidencing the preference for [2?+?3]-annulation over the [4?+?2]-Diels-Alder alternative. The reaction involves initial nucleophilic addition of the pyrrole moiety at the triple bond followed by tandem ring closure of an anionic intermediate.     

Two approaches toward the regio- and stereoselective synthesis of N-unsubstituted 3-aryl-4-(trifluoromethyl)-4H-spiro-[chromeno[3,4-c]pyrrolidine-1,3'-oxindoles]

Chemistry of Heterocyclic Compounds - A regio- and stereoselective method for the synthesis of N-unsubstituted 3-aryl-4-(trifluoromethyl)-4H-spiro[chromeno[3,4-c]-pyrrolidine-1,3'-oxindoles] in...     

Stereoselective 1,3-dipolar cycloaddition of unsaturated nitriles to isoquinolinium ylids. Molecular and crystal structure of 1,2-trans-3,3-dicyano-1-carbamoyl-2-(3-pyridyl)-1,2,3,4-tetrahydrobenzo[f]indolizine

The reactions of isoquinolinium ylids with arylmethylenemalononitriles proceed highly stereoselectively via a pathway involving synchronous 1,3-dipolar cycloaddition to give 1,2-trans-2-aryl-3,3-dicyano-1-carbamoyl(benzoyl)-1,2,3,4-tetrahydrobenzo[f]indolizines. The regiospecificity and stereospecificity of these reactions were confirmed by the results of PMR spectroscopy and x-ray diffraction analysis.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1248–1254, September, 1991.     

Stereochemistry of the reaction of pyridinium ylides with α,Β-unsaturated nitriles

Regioselective and stereoselective methods were developed for the synthesis of 4-aryl-2-oxo-3-(1-pyridinio)-5-cyano-3,4-trans-1,2,3,4-tetrahydropyridin-6-olates from pyridinium ylides and ,-unsaturated nitriles. The compounds were also obtained by the condensation of aromatic aldehydes, cyanoacetamide, and pyridinium ylides. It was established that these reactions take place through the corresponding Michael adducts, which undergo heterocyclization in the form of the anti conformers to substituted 3,4-trans-1,2,3,4-tetrahydropyridin-6-olates.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 363–369, March, 1990.     

Palladium catalysed regio- and stereoselective synthesis of (E)-4-aryl-1,3-bis(trimethylsilyl)but-3-en-1-ynes

A practical and general synthetic approach to a series of 4-aryl-but-3-en-1-ynes is described. In the presence of palladium complexes a variety of aryl bromides (or iodides) undergo coupling with two equivalents of trimethylsilylacetylene with the formation of (E)-4-aryl-1,3-bis(trimethylsilyl)but-3-en-1-ynes. The protocol is simple, efficient, and affords synthesis of regio- and stereoselectively target products in good to high yields.     

Palladium-catalyzed construction of amino acid derivatives possessing vicinal chiral quaternary and tertiary carbon centers at the α and β positions

The palladium catalyzed regio- and diastereo-selective allylic alkylation of (R)-2-acetoxy-4-aryl-3-butene with N-(diphenylmethylidene)glycinate and N-(diphenylmethylidene)alaninate occurred. The stereochemistry was controlled by the use of o-(diphenylphosphino)carboxylic acid, and produced new amino acid derivatives possessing vicinal chiral quaternary and tertiary carbon centers at the α and β positions.     

Diastereoselective heterocyclization of geminal bromo-fluoro arylcyclopropanes by nitrosonium tetrafluoroborate: Access to 4-fluorinated isoxazolines and isoxazoles

A series of 5-aryl-4-bromo-4-fluoroisoxazolines was synthesized via nitrosation of 2-aryl-1-bromo-1-fluorocyclopropanes with NOBF₄. It was shown that the E-isomers of the cyclopropanes react highly regio- and diastereoselectively leading exclusively to the E-isomers of the isoxazolines. The obtained 5-aryl-4-bromo-4-fluoroisoxazolines were transformed selectively into the corresponding 5-aryl-4-fluoro- or 5-aryl-4-bromoisoxazoles in good yields in the reaction with Lewis acids.     

Expedient Approach for the Synthesis of Trispiropyrrolidine Bisoxindoles Through 1,3-Dipolar Cycloaddition Reactions

A series of trispiropyrrolidine bisoxindoles has been achieved via a three-component 1,3-dipolar cycloaddition reaction of 3-aryl-5-arylmethylenespiro[indole-3′,2-[1,3]thiazolane]-2′(1H),4-dione, isatin, and sarcosine in refluxing toluene, which produced the corresponding cycloadducts in good yields (79–88%). Their structures were determined by infrared, ¹H and ¹³C NMR, elementary analysis, and single-crystal x-ray diffraction analysis, and the cycloaddtion reaction was found to be highly regio- and stereoselective.     

Regio- and stereoselective homocoupling of gamma-arylated tert-propargyl alcohols with liberation of a ketone molecule and successive cyclization to produce fluorescent dihydrofuran derivatives

1,1-Disubstituted 3-aryl-2-propyn-1-ols undergo unprecedented regio- and stereoselective homocoupling with liberation of a ketone molecule in the presence of a rhodium catalyst to give the corresponding 2-hydroxymethyl-(E)-enynes. The subsequent cyclization of the enynes in the presence of a base affords fluorescent 2,3-dihydrofuran derivatives.     

Mechanism of ring opening of cis- and trans-1-methyl-2-aryl-3-aroylaziridine perchlorates under the influence of alcohols

The corresponding threo- and erythro-1,3-diaryl-3-alkoxy-2-N-methylamino-1-propanones, which are formed regio- and stereospecifically, were obtained by the reaction of cis- and trans-1-methyl-2-aryl-3-aroylaziridine perchlorates with alcohols.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1054–1058, August, 1989.     

Regio- and stereoselective cross-coupling of tert-propargyl alcohols with bis(trimethylsilyl)acetylene and its utilization in constructing a fluorescent donor-acceptor system

1,1-Disubstituted 3-aryl-2-propyn-1-ols undergo regio- and stereoselective cross-coupling on treatment with bis(trimethylsilyl)acetylene in the presence of a rhodium catalyst via cleavage of C(sp)-C(sp3) and C(sp)-Si bonds to produce the corresponding 2-hydroxymethyl-(E)-enynes. The subsequent desilylative Sonogashira coupling followed by base-promoted cyclization affords fluorescent dihydrofuran derivatives.     

Stereoselective synthesis and structure of 3,4-trans-6-amino-4-aryl-3-carbamoyl-5-cyano-1,2,3,4-tetrahydropyridin-2(1H)-thiones

Condensation of thiocarbamoylacetamide with arylidenemalononitrile or the three-component condensation of thiocarbamoylacetamide with aldehydes and malononitrile in the presence of triethylamine occurred regioselectively to give triethylammonium-6-amino-4-aryl-3-carbamoyl-5-cyano-1,4-dihydropyridine-2-thiolates. Protonation of the latter occurred stereoselectively to give 3,4-trans-6-aryl-3-carbamoyl-5-cyano-1,2,3,4-tetrahydropyridin-2(1H)-thiones. The¹H NMR spectrum and single x-ray crystallography indicate that the dihydropyridine ring has he sofa conformation with trans-pseudodiaxial orientation of the Ar and CONH₂ groups and trans-pseudoequatorial orientation of atoms 3-H and 4-H.N. D. Zelinskii Organic Chemistry Institute, Russian Academy of Sciences, Moscow, 117913. A. N. Nesmeyanov Institute of Elementoorganic Chemistry, Russian Academy of Sciences, Moscow, 117813. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1376–1382, Octoberm 1996. Original article submitted June 10, 1996.