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121.
122.
-Benzylidene--2,4,6-tri--butylphenylphosphine containing phosphorus in low coordination state was irradiated to give the corresponding -isomer: both isomers were isolated and characterized and the reactions with chromium(O) carbonyls were described. 相似文献
123.
The title compound 4 is generated from the phosphoric amide 5 in tetrahydrofuran with butyllithium. The lithium reagent 4 is stable at room temperature; its reactions with electrophiles furnish the products 6–22 , 26 , 27 , see Table 1 and the Scheme. A second alkylation is also possible, see 23–25 . The cleavage to tetrahydroisoquinolines is accomplished in refluxing aqueous-methanolic hydrochloric acid, see Table 2. Phosphinoylation, lithiation, reaction with electrophiles and cleavage constitute an efficient sequence for 1-alkylation of the isoquinoline nucleus. 相似文献
124.
(Z)-1-Chloro-2-(2,4,6-tri-tert-butylphenyl)-2-phosphaethenyllithium was allowed to react with bis(diisopropylamino)-phosphenium triflate to afford the corresponding 1,3-diphosphapropene which was converted to 3-thioxo-1,3-diphosphapropene [(Z)-Mes*P = C(Cl)-P(= S)(NiPr2)2]. The coordination properties of 3-thioxo-1,3'-diphosphapropene were investigated with carbonyltungsten(0) and dichloroplatinum(II) reagents, and the molecular structure of the chelate dichloroplatinum(II) complex was unambiguously determined by X-ray crystallography together with the free ligand. The dichloroplatinum(II) complex underwent intramolecular cyclisation involving C-H activation to give a 5,7-di-tert-butyl-3,3-dimethyl-l-(phosphinomethyl)-1-phosphaindane derivative as well. 相似文献
125.
126.
Rader S. Jensen Anil S. Gajare Masaaki Yoshifuji Fumiyuki Ozawa 《Tetrahedron letters》2005,46(50):8645-8647
A palladium complex bearing 1,2-diphenyl-3,4-diphosphinidenecyclobutene ligand (DPCB) has been used to facilitate the catalytic cyanation of aryl bromides. A series of substituted benzonitriles was prepared in good to high yields by the treatment of the corresponding aryl bromides with Zn(CN)2 in N-methyl-2-pyrrolidone in the presence of 2-4 mol % catalyst at 100 °C for 16 h. 相似文献
127.
128.
[reaction: see text] Sterically protected (Z)-1-(2,4,6-tri-tert-butylphenyl)-2,5-dibromo-1-phosphapent-1-ene was allowed to react with potassium tert-butoxide to afford a cyclopropylidenephosphaethene, which was characterized spectroscopically and by X-ray crystallography. Construction of the cycloalkyl groups and isomerization of 1-phosphapenta-1,2,4-trienes to cyclopropylidenephosphaethenes are also described. 相似文献
129.
130.
Shigekazu Ito Sou Hashino Masaaki Yoshifuji Masae Takahashi Yoshiyuki Kawazoe 《Tetrahedron》2007,63(41):10246-10252
Due to a facile head-to-tail [3+2] dimerization, even a sterically demanding group such as the Mes∗ (2,4,6-tri-tert-butylphenyl) group around the PCC moiety did not allow us to isolate 3-(4-cyanophenyl)-1-(2,4,6-tri-tert-butylphenyl)-1-phosphaallene from the elimination reaction of 2-bromo-3-(4-cyanophenyl)-1-(2,4,6-tri-tert-butylphenyl)-1-phosphaprop-1-ene with DBU (1,8-diazabicyclo[5.4.0]undec-7-ene), and the corresponding 1,4-diphosphafulvene containing cyano groups was obtained and characterized. Theoretical studies on the [3+2] dimerization of phosphaallene characterize possible intermediates affording 1,4-diphosphafulvenes and also suggest the cyano group effect to facilitate the saturation of the PC double bonds. On the other hand, 1,2-bis(4-cyanophenyl)-3,4-bis[(2,4,6-tri-tert-butylphenyl)phosphinidene]cyclobutene was obtained from 2-bromo-3-(4-cyanophenyl)-3-trimethylsiloxy-1-(2,4,6-tri-tert-butylphenyl)-1-phosphaprop-1-ene together with the 3-(4-cyanophenyl)-1-phosphaallene. 相似文献