A. G. Ibragimov

Synthesis of N-aryl-1,5,3-dithiazepanes and N-aryl-1,5,3-dithiazocanes in the presence of samarium- and cobalt-containing catalysts

Efficient procedures were developed for the synthesis of N-aryl-1,5,3-dithiazepanes and N-aryl-1,5,3-dithiazocanes by cyclocondensation of anilines with formaldehyde and α,ω-dithiols (etane-1,2-dithiol and propane-1,3-dithiol), as well as by transamination of N-tert-butyl-1,5,3-dithiazepane or N-tert-butyl-1,5,3-dithiazocane with aromatic amines in the presence of samarium and cobalt complexes.

First preparative synthesis of alumocyclopentanes involving zirconium complexes

M. Dzhemilev, A. G. Ibragimov, A. P. Zolotarev, R. R. Muslukhov, and G. A. Tolstikov UDC 542.97:547.514+547.256.2 We have recently published several communications on the carbometallation of ~-olefins using diethylmagnesium in the presence of catalytic amounts of Cp2SrCI 2 [i, 2]. Diethylalu ~ minum chloride by the action of TiCI~ or Ti(OBu) 4 [3], and triethylaluminum with two-compon- ent catalysts consisting of Cp2ZrCI 2 + 6Et2Mg or Cp2ZrCI 2 + 6(i-Bu)3Al [3]. In a continuation of a study of these reactions, we have established that, in contrast to the Cp2ZrCI 2 + 6Et=Mg catalyst, the reaction of Et3AI with ~-olefins, such as l-hexene, l-octene, and l-undecene, in the presence of Cp2ZrCl 2 taken in Et3Al:e-olefin:Cp2ZrCl 2 mole ratio equal to (100-120):100:2 at about 20~ over 6-8 h gives the corresponding alumocyclo- pentanes (Ia)-(!c) in 80-95% yields with high selectivity. Datta et al. [4] have proposed that the formation of alumocyclopentanes under the reac- tion conditions proceeds through the formation of zirconocyclopentanes according to scheme: EhAI q- Cp2ZrCl2 /- /\/\/--R -. C~Zr

Effective synthesis of N-aryl-substituted 1,5,3-dithiazepinanes and 1,5,3-dithiazocinanes

Selective methods were developed for the synthesis of N-aryl-1,5,3-dithiazepinanes and N-aryl-1,5,3-dithiazocinanes by transamination of N-tert-butyl-1,5,3-dithiazepinane or recyclization of 1-oxa-3,6-dithiacycloheptane and 1-oxa-3,7-dithiacyclooctane by the action of aniline derivatives in the presence of Sm(NO3)3·6H2O catalyst.

Synthesis and transformations of “non-grignard” organomagnesium reagents obtained from 1,3-dienes

Abstract This paper is the first attempt to systematize availabe published data on the synthesis and transformations of unsaturated organomagnesium compounds obtained from 1,3-dienes by nontraditional methods. Direct metallation of 1,3-dienes and polyenes by chemically activated highly active magnesium is reviewed. Some results of hydro- and carbon-magnesiation of unsaturated componds by hydride and alkyl magnesium derivatives are cited including those obtained with homogenous metal complex catalysts. Attention is focused also on metallation of cyclic 1,3-dienes by highly active magnesium or Grignard reagents and some of their analogues. The structure and chemistry of non-trivial organomagnesium compounds are also discussed.

First example of one-pot synthesis of hydrocarbon macrorings

Cyclomagnesation of α,ω-diallenes by EtMgBr in the presence of chemically activated Mg and Cp2TiCl2 catalyst led to the formation of cyclic organomagnesium compounds whose hydrolysis provided gigantic hydrocarbon macrorings with 1,5-cis-disubstituted double bonds.

Catalytic cyclopropanation of fullerene[60] with diazomethane

The selective cyclopropanation of C60-fullerene with diazomethane was performed under the catalysis with Pd(acac)2, and individual 5,6-open and 6,6-closed cycloadducts were obtained.

Catalytic [2+1]-cycloaddition of ethyl diazoacetate to fullerene [60]

Cyclopropanation of C60-fullerene was performed with ethyl diazoacetate in the presence of Pd(PPh3)4 catalyst. A probable reaction mechanism is suggested.

N,N,N′,N′-tetramethylmethanediamine—A new reagent for aminomethylation of acetylenes

A new procedure has been developed for aminomethylation of terminal acetylenes with N,N,N′,N′-tetramethylmethanediamine in the presence of transition metals and lanthanide complexes and salts. The procedure ensures formation of the corresponding N,N-dimethylprop-2-yn-1-amines with high yield and selectivity.

Synthesis and conversions of metallocycles. 22. NMR studies of the mechanism of Cp2ZrCl2-catalyzed cycloalumination of olefins with triethylaluminum to form aluminacyclopentanes

The mechanism of cycloalumination of olefins under the action of AlEt3 in the presence of Cp2ZrCl2 giving rise to aluminacyclopentanes was investigated by dynamic 1H and 13C NMR spectroscopy. The bimetallic complex Cp2ZrEtCl–AlEt3 is formed initially and is converted into the bridged complex Cp2Zr(Cl)CH2CH2AlEt2 as a result of beta-hydride shift and elimination of the ethane molecule. The resulting complex adds a molecule of the initial olefin yielding aluminacyclopentanes. Under the action of Et2AlCl in the presence of an excess of AlEt3, zirconacyclopentanes give rise to intermediate bimetallic complexes stable at -70 °C. Under the reaction conditions, the latter compounds are converted into aluminacyclopentanes.

First synthesis of magnesacyclopentadienes from acetylenes by treatment with BuMgHlg in the presence of Zr complexes

Treatment of internal acetylenes and allenes with BuMgHlg (Hlg = Cl, Br) in the presence of Cp2ZrCl2 selectively leads to the formation of substituted magnesacyclopenta-2,4-dienes and alkylidenemagnesacyclopentenes.