L. I. Zakharkin

Selective fluorination of o0 and m-carboranes. Synthesis of 9-monofluoro-, 9,12-difluoro-1,8,9,12-trifluoro-, and 8,9,10,12-tetrafluoro-o-carboranes and 9-monofluoro-, and 9,10-difluoro-m-carboranes. Molecular structure of 8,9,10,12-tetrafluoro-o-carborane

Abstract Reaction of o - and m -carboranes 1 with antimony pentafluoride results in replacement of hydrogen by fluorine at the boron atoms, to give in succession 9-fluoro-; 9,12-difluoro-; 8,9,12-trifluoro-; 8,9,10,12-tetrafluoro- o -carboranes and 9-fluoro-; 9,10-difluoro- m -carboranes. An X-ray structural study of the 8,9,10,12-tetrafluoro- o -carborane has been carried out. The compounds synthesized have been characterized by elemental analysis and 1 H, 11 B{ 1 H}, 19 F NMR spectroscopy.

Synthesis and some reactions of carbenium ions of new types stabilized with π-cyclopentadienyl-π-(3)-1,2-dicarbollyl-iron (II) group. Structure of 3-π-C5H5FeII-π-1,2-C2B9H-10-1-C+HC6H5

Abstract Stable carbenium zwitterions 3-π-C5H5FeII-π-1,2-C2B9 H - 10-1-+CRR′ (Rue5fbR′ue5fbH; Rue5fbH, R′ue5fb=Me; Rue5fbH, R′ue5fbPh; Rue5fbR′ue5fbMe) have been prepared by protonation of the carbinols [3-π-C5H5FeII-π-1,2-C2B9H10-1-CH(OR)R]− (Rue5fbH, Me, Ph) and olefins [3-π-C5H5FeII-1,2-C2B9H10-1-C(R)ue5fbCH2]− (Rue5fbH, Me). Reactions of the zwitterions with neutral and charged nucleophilic reagents have been studied. Crystal and molecular structure of 3-π-C5H5FeII-π-1,2-C2B9H10-1- C + HC6H5 have been established. The possibility of direct stabilization of a carbocationic centre by the iron atom was shown. Various derivatives ofπ-cyclopentadienyl-π-(3)-1,2-dicarbollyliron(III) were obtained.

Metallacarborane diene π-complexes. I. Synthesis of rhodacarboranes with a η2,η3-2-methylenenorbornadienyl ligand at the rhodium vertex

Abstract Novel 18-electron rhodacarboranes with a 2-methylenenorbornadienyl ligand, η 2 ,η 3 -coordinated to a rhodium atom of closo-3,3-(η 2 ,η 3 -C 7 H 7 CH 2 )-1,2-R 1 R 2 -3,1,2-RhC 2 B 9 H 9 (IIIa–IIId, R 1 ue5fb R 2 ue5fb H (a), R 1 ue5fb R 2 ue5fb Me (b), R 1 ue5fb Me or Ph, R 2 ue5fb H (c,d) and closo-2,2-(η 2 ,η 3 -C 7 H 7 CH 2 )-2,1,7-RhC 2 B 9 H 11 (VIII) have been prepared. The structures of IIIa–IIId, and VIII were deduced from their IR, 1 H NMR and 13 C NMR spectra. Two alternative synthetic routes to the above complexes have been suggested: (a) reactionis of 16-electron complexes of (η 4 -C 7 H 7 -2-CH 2 OH)- Rh(acac) or [(η 4 -C 7 H 7 -2-CH 2 OH)RhCl] 2 with appropriate dicarbollide anions with a subsequent acidificatiion by HPF 6 and (b) reactions of unsubstituted and C-mono-substituted closo-bis(triphenylphosphine)hydridorhodacarboranes with 2-(hydroxymethyl)norbornadiene on heating in benzene. The possible mechanisms of these reactions are discussed. An X-ray study of complex IIIb, R 1 ue5fb R 2 ue5fb Me, confirms that there is allylolefin type metal-ligand bonding.

Synthesis of binuclear rhodacarboranes from 1,4-and 1,3-C6H4(CH2-9-C2H2B9H9-7,8-nido]22− dianions and (Ph3P)3RhCl

Abstract1,4- and 1,3-C6H4(CH2-9-C2H2B9H9-7,8-nido]22− dianions obtained fromnido-7,8-dicarbollide ion and 1,4-bis(bromomethyl)- and 1,3-bis(bromomethyl)benzenes react with (Ph3P)3RhCl to give binuclear rhodacarboranes, 1,4- and 1,3-[3,3-(Ph3P)2-3-H-3,1,2-RhC2B9H10-4-CH2]2C6H4.

Destruction ofB-polyfluorosubstitutedo-carboranes into anions ofB-fluorosubstitutednido-7,8-dicarbaundecaborates by the action of ethanolic alkali and amines

The destruction ofB-polyfluorosubstitutedo-carboranes by the action of ethanolic alkali and amines was studied. The destraction of trifluoro-o-carborane was found to occur regioselectively. The nature of the amine was shown to affect the stereochemistry of the destruction of trifluoro-o-carborane. The intermediate of the reaction of tetrafiuoro-o-carborane with diethylamine was detected.

Synthesis of 9-benzyl-o- and 9-benzyl-m-carboranes containing functional substituents in the benzene ring by electrophilic alkylation ofo- andm-carboranes by the correspondingR-benzyl halides

Abstract9-Benzyl-o- andm-carboranes containing NO2, COOH, COOMe, and COPh groups in thepara-position of the benzene ring were synthesized by the Friedel—Crafts reaction.

Synthesis and some reactions of the stable carbocations stabilized by the 1-[closo-3,3,3-(CO)3-3,l,2-ReC2B9H10]−group. The structure of closo-3,3,3-(CO)3-3,1,2-ReC2B9H10−-1-C+Me2

Abstract The stable carbenium cations in the zwitterionic complexes closo-3,3,3-(CO)3- 3,1,2-ReC2B9 H 10-1- C +RR′ (R = R′ = H; R = H, R′ = Me; R = R′ = Me) have been prepared by protonation of closo-3,3,3-(CO)3-3,1,2-ReC2B9H10-1-CH2OR (R = H, Me) and closo-3,3,3-(CO)3-3,l,2-ReC2B9H10-1-CRue5fbCH2 (R=H, Me). Some of the reactions of the zwitterions with neutral and charged nucleophilic reagents have been studied. The crystal and molecular structure of closo-3,3,3-(CO)3-3,1,2-ReC2B9 H 10- 1- C + Me2 has been established. It is shown that the carbocationic centre in these zwitterions is stabilized by direct Reue5f8C interaction.

Facile synthesis of (±)-2,6-dimethyloctan-1-ol formate, the biologically active analog of the smaller flour beetle aggregation pheromone, from 1-allyloxy- and 1-benzyloxy-2,6-dimethyl-2,7-octadienes, the telomers of isoprene with allyl and benzyl alcohols

A careful investigation of the telomerization of isoprene with allyl, benzyl, 2-chloroethyl and methyl alcohols on π-allylpalladium complex catalysts was carried out. The structures of the obtained telomers were determined by1H NMR spectroscopy. 1-Alkoxy-2,6-dimethyl-2,7-octadiene is a predominant telomer. 2,6-Dimethyloctan-1-ol, which reacts with HCOOH to give (±)-2,6-dimethyloctan-1-ol formate in high yield, was obtained from 1-allyloxy- and 1-benzyloxy-2,6-dimethyl-2,7-octadienes by the removal of allyl and benzyl protective groups and by the hydrogenation of double bonds.

Formation of stable carbenoid α-methoxyorganolithium compounds, 1-alkyl-2-lithiummethoxymethyl-o-carboranes, by metalation of 1-alkyl-2-methoxymethyl-o-carboranes withn-butyllithium

Abstract1-Alkyl-2-methoxymethyl-o-carboranes are easily metalated withn-butyllithium in an ether-benzene solution to form carbenoid 1-alkyl-2-lithiummethoxymethyl-o-carboranes, which are stable at room temperature. Under the action of H2O, CO2, and PhCHO these lithium carboranes yield the starting compounds, carboxylic acids, and benzyl alcohols, respectively.

Synthesis of ω-(2-oxocyclododecyl)alkanoic acids by alkylation of cyclododecanone with ω-haloalkanoic esters under conditions of phase-transfer catalysis

Abstract(ω-(2-Oxocyclododecyl)alkanoic acids have been obtained by alkylation of cyclododecanone with alkyl 3-bromopropionate, 5-iodopentanoate, and 11 -bromoundecanoate under conditions of phase-transfer catalysis.