Unusual reaction of iodofurazans with nucleophilic reagents

Nucleophilic reagents cause detachment of the iodine atom from 3-iodo-4-R-furazans and opening of the furazan ring to give salts of the corresponding -hydroxyiminoacetonitriles.     

Generation of cyclohexene-s-phenylepisulfonium fluoborate and its reaction with nucleophilic reagents

Conclusions It was shown that a stable intermediate of the episulfonium ion type can be generated by the reaction of cyclohexene with phenylsulfenyl fluoborate, and its reactions with nucleophilic reagents were studied.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 12, pp. 2832–2834, December, 1974.     

Mechanistic studies on the nucleophilic reaction of porphyrins with organolithium reagents.

Porphyrins react readily with organolithium reagents under substitution of free meso positions. As this method has proven to be very versatile for the preparation of a wide range of meso substituted porphyrins, a mechanistic study of the reaction was undertaken using 5,15-diaryl- and dialkyl substituted porphyrins, 2,3,7,8,12,13,17,18-octaethylporphyrin, and the respective nickel(II) complexes. A combination of deuteration experiments, electronic absorption spectroscopy of the reactive intermediates, trapping of intermediates with organic electrophiles, and reaction at different pH values showed significant differences in the reaction pathways of free base porphyrins and metalloporphyrins. In both cases the reaction proceeds initially under formation of phlorin like intermediates which are stable in water. For the Ni(II)phlorins a mesomeric carbanionic form with a highly distorted structure exists that can react as a nucleophile with electrophiles such as RI, H+, or D+. In the latter case a protonation-deprotonation equilibrium involving porphodimethen intermediates has to be assumed. Free base phlorins do not react as nucleophiles but can undergo H/D exchange reactions in strongly acidic media.     

Creation of quaternary stereocenters by the addition of allyltributyltin to chiral cyclic N-acyliminium ions

5,5-Disubstituted pyrrolidinones and 5-substituted pyrrolidinones were obtained with moderate to good diastereoisomeric excess through the cis addition of allyltributyltin and triethylsilane, respectively, to the 4-OTBS group in the N-acyliminium ion prepared from the corresponding 5-hydroxy lactams. Cyclization of an N-allyl-5-propargyl pyrrolidinone and N-allyl-5-allyl-5-substituted pyrrolidinones using Grubbs’ catalyst led to the preparation of a dehydropyrrolizinone and dehydroindolizinones containing a quaternary stereocenter.     

The reaction of metallic mercury with alkyl halides in the presence of nucleophilic reagents

Russian Chemical Bulletin -     

Asymmetric thio-Michael/nucleophilic addition domino reaction with chiral N-sulfinimines

Optically active N-sulfinimines underwent stereoselective Michael/nucleophilic addition domino reaction triggered by magnesium thiolate to give alpha-phenylthiomethyl-beta-(N-sulfinylamino) esters in high diastereomeric excess. The adducts were readily converted into optically active alpha-methylene-beta-(N-sulfinylamino)esters so that this reaction provides a useful asymmetric aza-Baylis-Hillman-equivalent method.     

Stereochemical studies on the nucleophilic substitution in the reaction of allyl phosphates with organoaluminium reagents

The reaction of cis- or trans-5-isopropenyl-2-methyl-2-cyclohexenyl diethyl phosphate (I) with Me₂AlX (X = OPh, SPh, NHPh) in hexane results in substitution of the -O-PO(OEt)₂ group with X under predominant inversion. The solvent effects on the stereochemistry in these reactions have been disclosed.     

Allylation of exocyclic N-Acyliminium ions generated from chiral N-[1-(phenylsulfonyl)alkyl]oxazolidin-2-ones

N-[1-(Phenylsulfonyl)alkyl]oxazolidin-2-ones are successfully prepared by condensation of the corresponding optically active oxazolidin-2-ones with aldehydes and benzenesulfinic acid. At low temperature, in the presence of titanium tetrachloride, these sulfones are converted into N-acyliminium ions, which react with allyltrimethylsilane with a variable degree of stereoselectivity. The best results are obtained with (R)-5,5-dimethyl-4-phenyloxazolidin-2-one as a chiral auxiliary. Cleavage of the oxazolidin-2-one ring with lithium/ammonia affords the corresponding homoallylamines, which reveal an absolute configuration opposite that expected on the basis of the usual steric effects. A complexation of the Lewis acid with the N-acyliminium ion may be responsible of this rather unusual stereochemical outcome.     

Reaction of aroylenebenzimidazoles with nucleophilic reagents

The reaction of aromatic mono- and bis(o-phenylenediamines), -(aminophenols), and -(o-aminothiophenols) with mono- and diaroylenebenzimidazoles in polyphosphoric acid was studied. The interrelationship between the structures and properties of the resulting compounds, which contain benzimidazole and other rings in the ortho position relative to one another, was investigated.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 247–252, February, 1972.     

Reaction of anthrapyridones with nucleophilic reagents

The present authors previously showed that anthrapyridone (7H-dibenz [f, ij] isoquinoline-2, 7 [3H] dione) (I) and N-methylanthrapyridone (II) react with aliphatic amines to give the corresponding 1-alkylaminoanthrapyridones [1]. Continuing the research, the reaction of anthrapyridones with other nucleophilic reagents has been studied. Boiling N-methylanthrapyridone with an aqueous dioxane solution of sodium hydroxide, gave a 50% yield of a compound which, after recrystallization from acetic acid had mp 299–300° C (decomp). Found: C 73.57, 73.71; H 3.80, 3.85; N 5.00, 5.22%. Calculated for C₁₇H₁₁NO₃: C 73.62; H 4.00; N 5.05%. The compound was identical in chemical properties, melting point, and IR spectrum with 1-hydroxy-N-methylanthrapyridone(III), prepared by the action of ethanolic alkali on 1-chloro-N-methylanthrapyridone(IV) by the method of [2].     

Interaction of N-halomethyl-N-nitramides with nucleophilic reagents

Conclusions The main features of the reaction of N-halomethyl-N-nitramides with nucleophilic reagents have been established.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 12, pp. 2738–2741, December, 1982.     

Isomerization of 3-aryl-4-sulfolenes and their reaction with some nucleophilic reagents

Bases convert 3-(4-substituted phenyl)-4-sulfolenes to 3-aryl-3-sulfolenes, which are subsequently isomerized to 3-aryl-2-sulfolenes. The ratios of the products depend on the character of the substituent in the phenyl ring, and electron-acceptor substituents accelerate the isomerization.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1072–1077, August, 1975.     

Acyclic stereoselection. 35. Effect of cation on diastereofacial selectivity in aldol reactions of a chiral α-silyloxy ketone.

By an appropriate choice of cation, three of the four possible aldols from the reactions of the chiral α-silyloxy ketone 1 with aldehydes may be obtained. The $\text{Z}$, lithium enolate provides 6, the $\text{Z}$, boron enolate gives 7, and the $\text{E}$ magnesium enolate affords 8.     

Synthesis and structure of reaction products obtained from 1,2-epoxyperfluorobutane and bifunctional nucleophilic reagents

1,2-Epoxyperfluorobutane readily reacts with bifunctional nucleophilic reagents to provide heterocyclic compounds with a pentafluoroethyl substituent. The reaction of this epoxide with thiourea and acetone thiosemicarbazone gave rise to 2-amino-5-pentafluoroethyl-5-fluoro-4(5H)-thiazolinone and 2-isopropylidenehydrazono-5-pentafluoroethyl-5-fluoro-4-thiazolidinone respectively. The reaction of 1,2-epoxyperfluorobutane with o-phenylenediamine and 2,3-diaminonaphthalene afforded in high yields 3-pentafluoroethyl-2(1H)-quinoxalinone and 3-(pentafluoroethyl)benzo[g]-2(1H)-quinoxalinone. The molecular and crystal structure of the obtained fluorine-containing heterocycles was established by XRD analysis.

     

β-Aziridinylacroleins in reactions with nucleophilic reagents

The reactivities of -aziridinylcinnamaldehyde and -(2-methylaziridinyl)acrylaldehyde with respect to amines, hydrazines, and semicarbazide were studied, -Aminoacroleins were obtained by reaction of secondary amines with aziridinylacroleins. The reaction of aziridinylcinnamaldehyde with primary amines gives the corresponding imines. It was established that in its reaction with hydrazines and semicarbazide aziridinylacrolein is more inclined to undergo heterocyclization reactions (the formation of pyrazoles and pyrazolines) than aziridinylcinnamaldehyde.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 483–488, April, 1978.     

A novel nucleophilic substitution of in situ generated 3-tert-butyldimethyl- silyloxyalk-2-enylsulfonium salts with allylindium reagents

[reaction: see text] In situ generated 3-tert-butyldimethylsilyloxyalk-2-enylsulfonium salts derived from the reaction of alpha,beta-enones with dimethyl sulfide in the presence of TBSOTf undergo a novel nucleophilic substitution with in situ generated allylindium reagents from indium and allyl halides to give silyl enol ethers of delta,epsilon-unsaturated ketones, which correspond to Michael addition products, in good yields.     

Synthesis of spirocyclic azacycles from the cyclization of furan tethered N-acyliminium ions

The protic and Lewis acid promoted cyclization reactions of tethered furan-4,5-dihydroxypiperid-2-ones, furan-4,5-diacetoxypiperid-2-ones and furan-3,4-diacetoxypyrrolid-2-ones, via their corresponding N-acyliminium ion intermediates, have been studied. In the case of the furan-4,5-dihydroxypiperid-2-one 2a and its diacetate derivative 2b, macrocyclic products were formed from an initial intermolecular reaction between 2a or 2b, via the nucleophilic C5 furan carbon, and their corresponding N-acyliminium ion intermediates. When the furan C5 position of 2b was blocked by substitution with bromine then TFA or Sc(OTf)₃ catalysed cyclization reactions gave a spirotricyclic product (a 5-6-6-tricycle) in a highly diastereoselective manner. Cyclization of the analogous C5-Br-furan-pyrrolidone 29 with TFA resulted in a related spirotricyclic (a 5-6-5 tricycle) product. Attempts to prepare an analogous azepine system, a 5-7-5 tricycle, were not successful. Cyclization reactions of the C5-PhS-furan- or C5-phenylsulfonyl-pyrrolidone analogues of 29 with TFA were also not successful.