Electrophilic dimerization of naphthols in the presence of aluminum halides

1. Download : Download full-size image

     

Cascade reaction of 2,3-naphthalenediol with benzene in the presence of aluminum halides

2,3-Naphthalenediol on superelectrophilic activation with aluminium halides smoothly reacts with benzene to give 4-((3-phenyl-1H-inden-1-yl)methyl)benzene-1,2-diol, which in turn undergoes intramolecular cyclization to form 5,10-methano-5-phenyldibenzo[a,d]cycloheptane-2,3-diol. The mechanistic aspects of these unusual transformations are discussed.     

Condensation of 2-naphthol and naphthalenediols with o-dichlorobenzene in the presence of aluminum halides

It is known that 1-naphthol, as a result of superelectrophilic (dicationic) activation in superacid media, is able to react with such deactivated aromatic compound as o-dichlorobenzene to give 4-(3,4-dichlorophenyl)-1-tetralone (2), which is a highly valuable intermediate in the synthesis of the antidepressant, sertraline (1) and other useful derivatives. However, the analogous reactivity of 2-naphthol and a variety of naphthalenediols towards o-dichlorobenzene has not been investigated thus far, although the corresponding tetralones, bearing dichlorophenyl moiety, could be of great pharmacochemical interest. In present work, we disclose that 1,5-, 1,6-, and 1,7- naphthalenediols (6a-c) react smoothly with o-dichlorobenzene in the presence of an excess of aluminum chloride or aluminum bromide to give the pairs of isomeric 4-(3,4-dichlorophenyl)- and 4-(2,3-dichlorophenyl)- 5-, 6-, and 7-hydroxy-1-tetralones (10a-c and 11a-c) in high overall yields. 2-Naphthol and 2,7-naphthalenediol (6d) exhibited comparatively lower reactivity, which however was sufficient to obtain the corresponding dichlorophenyl-2-tetralones in moderate yields. The mechanism of these reactions involving superelectrophilic dicationic or even tricationic intermediates, is discussed.     

Reactions of organochlorosilanes with chloro-and organogermanes in the presence of aluminum chloride

The effect of substituents at the silicon and germanium atoms in reactions of organochlorosilanes with chloro-and organogermanes in the presence of aluminum chloride was studied. The only occurring process is the exchange of the chlorine atoms at Ge for the phenyl groups from Si; an increase in the number of methyl groups or chlorine atoms at Si promotes formation of phenyltrichlorogermane, and an increase in the number of phenyl groups or replacement of the chlorine atom at the Si atom by hydrogen leads to the formation of di-and triphenylchlorogermanes. Neither phenyl nor other radicals are transferred back from Ge to Si in the course of reactions of phenylgermanes with methylchlorosilanes in the presence of aluminum chloride; the only occurring processes are the exchange of the phenyl or methyl radicals bonded to Ge for the Cl atom bonded to Al and the disproportionation of phenylchlorogermanes.     

Reactions ofN-pentafluorophenylcarbonimidoyl dichloride with aromatic hydrocarbons in the presence of aluminum chloride

N-Pentafluorophenylcarbonimidoyl dichloride reacts with aromatic hydrocarbons (benzene, toluene, xylenes, and mesitylene) in the presence of AlCl₃ to give stableN-pentafluorophenylbenzimidoyl chlorides, which can further react with aromatic hydrocarbons to give azomethine derivatives. An increase in the number of methyl groups in the molecule of a hydrocarbon favors the reaction.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1605–1611, September, 1993.     

Reactions of β-nitrostyrenes with tert-butylmercury halides in the presence of lodide lon

Photolysis of t-BuHgCl/KI with PhC(R²)C(R¹)NO₂ forms PhC(R²)C(R¹)Bu-t when R¹ = R² = H or in low yield when R¹ = H, R² = Ph. When R¹ ≠ H, or when R² = Ph, reactions with t-BuHgI/KI/hv proceed mainly via PhC(R²)C(R¹)NO₂·-, PhC(R²)C(R¹)N(OBu-t)O⁻HgX⁺, PhC(R²)C(R¹)NO and PhC(R²)C(R¹)N(OBu-t)HgX to form a variety of novel products including the dimeric bisnitronic esters ( 6 ) with R¹ = Me or Ph and R² = H; PhCH(R²)C(R¹) = NOBu-t with R¹ = Me or Ph and R² = H or R¹ = H and R² = Ph; PhC(R²)(OBu-t)C(R¹)NOH with R¹ = H or Me and R² = Ph; and 3-phenyl-2-R¹-indoles with R¹ = H, Me, Ph, PhS or t-BuS and R² = Ph. Nitrosoaromatics react with t-BuHgX in the dark to form ArN(OBu-t)(OBu-t)HgX⁺ which condenses with ArNO to form the azoxy compound. tert-Butyl radicals will add to RNO₂ [R = Ph, Ph₂CCH, Ph₂CC(Ph)] in the presence of t-BuHgI₂⁻ to form products derived from RN(OBu-t)O⁻HgI⁺.     

Reactions of trifluoromethyl-substituted arylacetylenes with arenes in superacids

Protonation of the C≡C bond in trifluoromethyl-substituted arylacetylenes ArC≡CCF₃ by the action of superacids (CF₃SO₃H or HSO₃F) generates vinyl cations ArC⁺=CHCF₃ which react with arenes Ar′H to give alkenes Ar(Ar′)C=CHCF₃. Protonation of the latter at the C=C bond in the reaction medium yields stable cations Ar(Ar′)C⁺-CH₂CF₃ which are converted into E/Z-isomeric alkenes Ar(Ar′)C=CHCF₃ and/or alcohols Ar(Ar′)C(OH)CH₂CF₃ as a result of quenching of superacid reaction solution.     

Reactions of phosphorus halides with urethane

By the reaction of phosphorus trichloride, thiophosphoryl chloride, phosphorus oxychloride and phosphorus pentachloride with urethane in stoichiometric ratio 1:1 or 1:2 in benzene, compounds of the type

and

(X = S, O or Cl; n = 1 or 2) have been synthesized. A probable mechanism for their formation has also been suggested.     

Reactions of isocyanates with compounds containing active methylene groups in the presence of triethylamine

Compounds containing active methylene groups react with isocyanates of different structures in the presence of triethylamine to form functionally substituted amides. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 2323–2330, October, 2005.     

Reactions of organic halides with organometallic compounds and terminal acetylenes catalyzed by palladium complexes

The results of the investigation of the cross-coupling of organometallic compounds and terminal acetylenes with organic halides catalyzed by transition metal complexes are generalized and analyzed. The influence of different factors on the rate and selectivity of catalytic cross-coupling is discussed. A detailed mechanism of the cross-coupling of Grignard reagents with organic halides is suggested. The cross-coupling reaction involving organotin compounds proceeds under very mild conditions in the presence of a ligand-free Pd catalyst. Examples of using catalytic cross-coupling of organic halides with organomagnesium, organozinc, and organotin compounds are presented.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 2148–2167, September, 1996.     

Polyhalomethanes combined with aluminum halides in one-step syntheses of carbonyl-containing compounds from alkanes and cycloalkanes

Data on new-generation superelectrophiles containing polyhalomethanes and aluminum halides are generalized. These systems open up broad prospects for organic syntheses based on alkanes and cycloalkanes. With these systems, reactions of various alkanes and cycloalkanes with CO were performed for the first time. Superelectrophiles underlay the development of new one-pot methods for the synthesis of carbonyl-containing compounds of various classes from readily available alkanes (or cycloalkanes) and CO. The reactions are usually selective and give the target products in high yields.     

Reactions of diazo ketones with activated unsaturated compounds in the presence of gallium trichloride

Diazoacetone reacts with methyl acrylate in the presence of anhydrous GaCl₃ to give isomeric methyl 2-acetylcyclopropanecarboxylates rather than pyrazolines obtained from diazo esters or by noncatalytic reactions. In a similar reaction, diazoacetophenone yields methyl 2-benzoylcyclopropanecarboxylates, benzoylmethyl acrylate, and benzoylmethyl 2-benzoylcyclopropanecarboxylate via partial transesterification. Addition of an equimolar amount of GaCl₃ to diazoacetone in the system CH₂Cl₂-HCl-H₂O unexpectedly produces 4,5-dimethylfuran-3(2H)-one and 1,1′-oxybis(propan-2-one).