Free-radical addition of 2-pyrrolidinone to α-olefins

Summary When reaction is initiated with t-butyl peroxide, 2-pyrrolidinone reacts with -olefins with formation of mixtures of 3- and 5-alkyl-2-pyrrolidinones with the latter isomer in the predominating amount.This article is published in accordance with a resolution of the Conference of Chief Editors of Journals of the Academy of Sciences of the USSR of July 12, 1962, as a dissertation paper by G. I. Nikishin.Translated from Izvestiya Akademii Nauk SSSR, Seria Khimicheskaya, No. 10, pp. 1843–1847, October, 1964     

A new route to α-alkyl-α-fluoromethylenebisphosphonates

A new route to α-alkyl-α-fluoromethylenebisphosphonates, 2 has been developed starting from commercially available tetraethyl fluoromethylenebisphosphonate (1), and alkyl halides using either caesium carbonate in DMF or sodium dimsyl. De-esterification of 2 provided biologically important α-alkyl-α-fluoromethylenebisphosphonic acid, 3, while alkoxide-induced carbon-phosphorus bond cleavage of 2 gave α-fluorophosphonates, 4, which are useful synthons in organic synthesis.     

A new route to heterocyclic α-dehydro α-amino esters

Heterocyclic α-dehydro α -amino esters are obtained by the reaction of ethyl N-carbomethoxy oxamate with ω-halogened phosphorus ylids.     

Palladium catalyzed ring opening of furans as a route to α,β-unsaturated aldehydes

Furans may be ring opened via pallado-catalyzed reactions leading to α,β-unsaturated aldehydes and ketones tethered to indole and isoquinoline moieties. Besides their synthetic interest, these fragmentations bring interesting elements into the discussion around the reaction mechanisms involved in palladium C-H activations of electron-rich heterocycles.     

Pd-catalyzed asymmetric conjugate addition of arylboronic acids to 2-nitroacrylates: a facile route to β-homophenylglycines

Asymmetric conjugate addition of arylboronic acids to 2-nitroacrylamide in the presence of cationic palladium–Chiraphos complex proceeds with high yield and enantioselectivity (73–89% ee) using as low as 0.05–0.25 mol % of the catalyst. The adducts can be smoothly transformed into the corresponding β²-homophenylglycines in two simple steps.     

Desilylation of α-trimethylsilylmethylene-δ-lactones. A new route to α-methylene-δ-lactones

Addition of phenylthiol to α-trimethylsilylmethylene-δ-lactones affords α-phenylthi(trimethylsilyl)methyl-δ-lactones which, on treatment with tetrabutyl-ammonium fluoride and methyl acrylate give the corresponding α-methylene-δ-lactones through a one-pot double deblocking process.     

Novel recyclization of 3,4-dihydroisoquinolines as an efficient route to a new type of heteroarylated derivatives of β-arylethylamines

A new recyclization of 3,4-dihydroisoquinolines is a convenient route to derivatives of new bbb-(o-benzothienylaryl)-and bbb-(o-thieno[2,3-b]pyridinylaryl)-containing ethylamines. These compounds look promising monoaminergic agents.     

Reaction of γ-(aminopropyl)siloxanes with phenolphthalein as a route to new siloxane-containing phenols

The reaction of γ-aminopropylorganosiloxanes with phenolphthalein yields monomeric and oligomeric N-alkylsiloxy-3,3-bis(4-hydroxyphenyl)phthalimidines. Their structures and compositions were confirmed by IR and NMR spectroscopy and by HPLC-MS. Studies by GLC and MALDI mass spectrometry showed that the action of the amine and of the water released in the reaction leads to the rearrangement of the siloxane bond in the course of the synthesis with the formation of linear and cyclic carbofunctional oligomeric siloxanephenols and mixed oligophenolaminosiloxanes. The possibility of modification of epoxy resins with the synthesized oligomers was revealed.     

The efficient consecutive β-carboxylation and α-alkylation of cyclic α,β-enones; a new route to sarkomycin

Sequential one-pot introduction of a carboxy group equivalent and an alkyl group at the respective β- and α-positions of cyclic enones has been achieved through a 1,4-addition reaction of [methoxy(phenylthio)(trimethylsilyl)methyl] lithium followed by direct trapping of the resulting enolate with alkyl halides. The present method proved to be applicable to a simple synthesis of sarkomycin.     

1,3-Dipolar cycloaddition of 3-phenylamino-5-phenylimino-1,2,4-dithiazole to 1-acyl-2-phenylacetylenes—A new route to functionalized 1,3-thiazole derivatives

3-Phenylamino-5-phenylimino-1,2,4-dithiazole reacted with 1-acyl-2-phenylacetylenes in ethanol or toluene on heating (78–80°C, 1 h) in chemo- and regioselective fashion to give previously unknown N-[5-acyl-3,4-diphenyl-1,3-thiazol-2(3H)-ylidene]-N′-phenylthioureas (yield 57–60%). The structure of N-[5-benzoyl-3,4-diphenyl-1,3-thiazol-2(3H)-ylidene]-N′-phenylthiourea was proved by X-ray analysis.     

Grob fragmentation of norbornyl α-diketones: a route to α-ketoenols and aromatic compounds

An efficient acid-catalyzed Grob fragmentation of symmetrical and asymmetrically substituted norbornyl α-diketones to the corresponding six-membered α-ketoenols is reported. The regio- and stereochemical outcome of the Grob fragmentation of C2 mono- and disubstituted α-diketones was investigated. A single regioisomer resulting from a favorable half-chair intermediate was normally observed. A departure from the normal course was noticed for C2 disubstituted α-diketones possessing an exo-methyl and an endo-methoxycarbonyl derivative, giving the opposite regioisomers due to initial formation of the hemiketal. The bromo analogues of the C2 disubstituted α-diketones furnished an unusual byproduct, which appears to have been formed through highly reactive fused four-membered bicyclo[2.2.0]hexane intermediates. A plausible mechanistic proposal involving the gem-dihalo intermediate, which in one case was actually isolated as its BF(2)-complex, is outlined. The fragmentation protocol was applied to various norbornyl substrates including bis-α-diketone derivatives. The methodology was successfully utilized for the synthesis of substituted aromatic compounds.     

Studies on polyhaloalkanes Ⅱ.A facile method for mono-fluorination of α,ω-dihaloperfluoroalkanes

A faeilo monofluorination of α,ω-dihaloporfluoroalkanes was achieved by the reactionof them with antimony trifluoride and chlorine in anhydrous antimony pentachloride when mono-fluorinated products wero removed immediately after their formation from the reaction mixture byfractionation.The reaction conditions were also investigated.     

Reaction of Schiff bases anions with α,ω-dihaloalkanes: Synthetic route to cyclic α-aminoacid derivatives.

Addition-elimination versus substitution reactions.     

Noscapine-derived β-amino alcohols as new organocatalysts for enantioselective addition of diethylzinc to aldehydes

In this paper, synthesis of two derivatives of noscapine and their application as organocatalysts in the asymmetric addition of diethylzinc to aromatic aldehydes is reported. The first catalyst (2) was synthesized by the reduction of lactone ring of noscapine to form the corresponding diol, and the second one (3) was prepared by tert-butyl dimethyl silylation of the primary hydroxyl group of 2. Excellent yields and high ees up to 95% were obtained by using 3 as the catalyst. To the best of our knowledge, this is the first report on the application of lactone ring opened noscapinoid compounds as organocatalysts in asymmetric reactions.     

Facile preparation of Nd_2Zr_2O_7–ZrO_2 nanocomposites as an effective photocatalyst via a new route

Nd_2Zr_2O_7–ZrO_2 nanocomposites were prepared via a facile process with propylene glycol as novel connecting agent and benzene tricarboxylic acid as a new complexing agent. The as-obtained Nd_2Zr_2O_7–ZrO_2 nanocomposites were characterized by transmission electron microscopy(TEM), UV–vis diffuse reflectance spectroscopy, energy dispersive X-ray microanalysis(EDX), Fourier transform infrared(FT-IR)spectroscopy, field emission scanning electron microscopy(FESEM), and X-ray diffraction(XRD). According to the morphological studies of the as-synthesized nanocomposites, it was found that the shape and particle size of Nd_2Zr_2O_7–ZrO_2 nanocomposites depended on the space-filling template type, dosage of space-filling template and tricarboxylic acid as complexing agent. Nd_2Zr_2O_7–ZrO_2 nanocomposites with different shapes and grain sizes have been synthesized. The photocatalytic behavior of as-produced Nd_2Zr_2O_7–ZrO_2 nanocomposites was also investigated through photodegradation of methylene blue dye and 2-naphthol as water pollutants.     

Diastereoselective addition of grignard reagents to chiral α-ketoacetals

High diastereoface—differenciating addition occurred in the reaction of chiral cyclic α-ketoacetals 1a and 1b with Grignard reagents     

Highly diastereoselective addition of allyltitanocenes to α-chiral ketones

The addition of allyltitanium reagents, generated by the desulfurizative titanation of allylic sulfides with the titanocene(II) reagent Cp₂Ti−1-butene, to α-chiral ketones produced tertiary homoallylic alcohols bearing three adjacent chiral centers with high diastereoselectivity.