A practical synthesis of [Ph3CH2F]BF4? is reported two routes, fluorination of [Ph3CH2OH]BF4? with DAST or hydrolysis of the phosphoranium salt, [Ph3FPh3]Br?. 相似文献
Reaction of the amines (CF3)2NX (X=Cl,Br) with norbornadiene either in solvent (CH2Cl2) at ?78 °C in the dark or in the vapour phase at 20 °C in daylight gives a mixture of 3-halogeno-5-(-bistrifluoromethylamino)nortricyclene (, -and , -isomers) and -5-(-bistrifluoromethylamino)- -7-halogenonorbornene in quantitative yield formed halonium ion addition to the diene. The reaction of the amine (CF3)2NBr in solvent Me2O or Et2O at ?78 °C in the dark gives the same products in low yield, together with 3-bromo-5-alkoxynortricyclene (, - and , -isomers) and the amine (CF3)2NR (R=Me, Et) in high yield. 相似文献
Optical absorption and emission spectra are reported for single crystals of the cubic elpasolite Cs2NaSmCl6. The variable temperature spectra obtained at high resolution are assigned using energies and relative intensities. Transitions from the ground level, 6H to cystal fi levels of 6H-, 6F-, 4G-, 4F,, 4I, and 6P, are located and characterized. Intensity calculations are reported for magnetic dipole allowed transitions. The dominance of vibronic intensity in 6H→6F - and 6P, transitions is accounted for qualitatively through the ligand polarization model involving quadrupole metal (Sm3+)-ligand (Cl?) interaction mechanisms. The Eu″(6H)→E′(6H) Eu′(6F) no-phonon transition is postulated to be pure electric quadrupole allowed. The ground state magnetic moment is determined to be very small from magnetic circular dichroism (MCD) spectra.This study has led to the assignment of nearly all of the crystal field levels in the visible and IR region for Cs2NaSmCl6. A total of 27 such levels were identified, 17 from no-phonon transitions and the rest from vibronic transitions. The magnetic dipole intensity calculated using intermediate coupling Oh wavefunctions along with a crystal field analysis of the splitting pattern was used in the assignment of the levels. Vibronic bands were observed for all transitions and their vibrational symmetries were tentatively assigned. MCD data were used to determine the magnet moment of the ground state. 相似文献
The diene reacted with CHCl3/aq. NaOH/PTC in CH2 Cl2 unexpectedly to give a mixture of the chlorination products and . Usual chlorination with Cl2 yielded similarly , , and dependent on the amount of Cl2. The formation of as well as the reaction of to give (besides ) shows an unusual Cl-Cl-interaction. 相似文献
Flash vacuum pyrolysis of -methylbenzyl chloride-,-2 gives benzocyclobutene-,-2. This finding indicates that the reaction involves net δ-elimination of hydrochloric acid. 相似文献
The lithium polyfluorobenzenesulphinates, Li O2SR (R = C6F5, -HC6F4, -HC6F4, or -HC6F4), and the dilithium tetrafluorobenzenedisulphinates, - and -(LiO2S)2C6F4, have been prepared by reaction of the appropriate polyfluoroaryllithium compounds with sulphur dioxide. All compounds were isolated as hydrates and gave the corresponding -benzylthiouronium salts on treatment with -benzylthiouronium chloride. From reactions of the lithium sulphinates with suitable mercuric salts in water, generally at room temperature, the derivatives RHgX (R = C6F5, X = Cl, Br, CH3CO2, or PhSO2; R = -HC6F4, X = Cl, Br, or CH3CO2; R = -HC6F4, X = Cl or Br; R = -HC6F4, X = Cl), -(XHg)2C6F4 (X = Cl, Br, or CH3CO2), and -(XHg)2C6X4 (X = Cl or Br) have been prepared. Similarly, the bispolyfluorophenylmercurials R2Hg (R = C6F5, -HC6F4, or -HC6F4) have been prepared from the corresponding lithium sulphinates and either mercuric salts or polyfluorophenylmercuric halides in aqueous -butanol. A possible mechanism for the sulphur dioxide elimination reactions is discussed. 相似文献
Oxidation of benzotropylium () fluoborate with Na2O2 and KO2 gives the benzotropones, and , as the major products with no naphthalene () or other ring contracted products formed. Oxidation with -chloroperoxybenzoic acid produces a small amount of naphthaldehydes ( and ) and even less naphthalene, a long with the benzotropones, while oxidation with H2O2 and -butyl peroxyacetate gives slightly more of the ring contracted naphthaldehydes than benzotropones, in addition to a small quantity of naphthalene. All reactions produce some 1,2-benzotropilidene () 相似文献
Treatment of methyl 3,5-dideoxy-β---pentofuranoside with the Ph3P-CCl4 reagent gave none of the expected 2-chloro derivative but a mixture of l→2 linked oligosaccharides, , with some higher homologues, terminated by αa 2-chloro-2,3,5-trideoxy-α---pentofuranosyl unit at the non reducing end. 相似文献
Alkylation of the distal double bond of pseudoionone has been carried out with isoprene epoxide (ZnCl2 /MeNO2 ) leading directly to α-, α- and γ hydroxyprenylionones. The α- and γ-isomers have been converted in few steps into the C50 carotenoids decaprenoxanthin and C.p. 450 respectively. 相似文献
Reaction of methyl 2-acetamido-4,6--benzylidene-2-deoxy-α---hexopyranosid-3-ulose with Me3SiCN afforded methyl 2-acetamido-4,6--benzylidene-3--cyano-2-deoxy-3--trimethylsilyl-α--- Reaction of ethyl 4,6-di--acetyl-2,3-anhydro-α--mannopyranoside with Me3SiCN gave the corresponding ethyl 4,6-di--acetyl-2--cyano-2-deoxy-α--glucopyranoside. Reaction of methyl 4,6--benzylidene-2,3-anhydro-α--allopyranoside or methyl 4,6--benzylidene-2,3-di--tosyl-α--glucopyranoside with Me3SiCN at - 75° or - 50° gave the corresponding methyl 6--[(R)-cyano phenyl methyl]-α--glyco-pyranosides with high or total regio and stereoselectivity. 相似文献
Two cyclohumulanoids, dl-bicyclohumulenone () and dl-africanol ( were synthesized through newly developed conformationally selective transannular cyclization of humulene 9,10-epoxide (). The epoxide was converted to a bicyclohumulenediol diacetate in 70% yield by treatment with BF3·OEt2-Ac2O, while treatment of with trimethylsilyl trifluoromethansulfonate gave an africen-10-ol (a and b) in 80% yield. The two intermediates and furnished the natural products and in 30 and 8 % yield from respectively. 相似文献
1-Phenylpentafluoropropene and its para-substituted analogs are susceptible to nucleophilic attack at both vinylic carbon atoms C-1 and C-2. They react with ethanolio sodium ethoxide to give predominantly substitution products, 1-ethoxy-1-phenyltetrafluoropropenes and 2-ethoxy-1-phenyltetrafluoropropenes , with only little formation of adducts, . 2-ethoxy-1H-1-phenylpentafluoropropanes . Alkenes , where the para-substituent X H,Cl,and CF3 give additionally 1,2-diethoxy-1-phenyltrifluoropropenes and, where X = CF3 also 2,2-diethoxy-1H-1-phenyltetrafluoropropane . Overall regioselectivity of nucleophilic attack of the ethoxide ion on alkenes exhibits the Hammett type correlation with Óp values of substituents X: CH3O and CH3 groups favour the attack on the vinylic carbon C-1, while CF3 and Cl substituents direct the attack on the C-2 carbon of alkenes . The E and Z isomers of 1-ethoxy and 1,2-diethoxy substituted alkenes and were formed in comparable amounts, while the E isomers of 2-ethoxy substituted alkenes were always formed with a 93 – 97 % selectivity. 相似文献
The synthesis and mechanism of formation of phosphonium salts of the type [R3CFXY]Z? (where X = F, Cl, Br; Y = Br, Cl; Z = Br, Cl), -phosphonium salts of the type [R3CF2R3]2Br?, and phosphoranium salts of the type [R3FR3]X? (X = Br, Cl) will be presented. The applicability of these substrates in the generation of useful nucleophilic or electrophilic synthetic intermediates will be discussed. 相似文献
Reductive coupling of methyl-vinyl ketone with TiCl4-Mg gives pinacol (25%). According to the reducing agents, mesityl oxide yields 2,4,5,7-tetramethyl-octa-2,4,6-triene (with 4TiCl3-LialH4), triene or 2,4,5,7-tetramethyl-octa-2,6-dien-4,5-diol (with TiCl4-Mg), pinacol (with VCl3-Mg), and 2-acetyl-1,3,3,4,4-pentamethyl-cyclopentane (with CrCl3-Mg or FeCl3-Mg or ZrCl4 or ZrCl4-Mg) as major products. 相似文献
The chlorinative ene-type reaction of isoprenoids ( → ) has been performed by electrolysis in CH2Cl2-H2O-NaCl system. The reaction provides useful allylic chlorides for terpene synthesis in high yields and is affected strikingly by the nature of halide ions and solvents. dl-Theaspirane was prepared from α-dihydroionol the electrolysis. 相似文献
A sequence of formylation followed by a carbene insertion reaction has led to the stepwise introduction of additional ethano bridges into 4,5,7,8- tetramethyl [22](1,4)cyclophane (), providing syntheses of 5,7,8-trimethyl- [23](l,2,4)cyclophane (), a mixture of 5,8-dimethyl[24(1,2,4,5)cyclophane () and 5,7-dimethyl[24(1,2,3,5)cyclophane (, and-4-methyl[25](1,2,3,4,5)-cyclophane (). This route to completes a formal eight-step synthesis of [26](1,2,3,4,5,6)cyclophane (, superphane) with an overall yield of 17%. A Birch reduction of readily gave 12,15-dihydro-5,7,8-trimethyl[23](1,2,4)-cyclophane () in 85% yield. 相似文献
The effect of the form and the parameters of the atom-atom potential of intermolecular interaction, as well as that of the approximations used in its summation over the atoms of a solid, on the values of the Henry constant 1 for the adsorption of noble gases on the basal face of graphite has been examined. At fixed values of the depth and of the position of the atom-atom potential minimum, 1 values are only slightly sensitive to the form of this potential, if its summation is performed taking into account the layer structure of graphite. Disregarding the laminated structure of the graphite lattice leads to highly underestimated values of 1. The values of the parameter 1 of the attractive forces of the potential (6, 8, exp) for the intermolecular interaction of the atoms of noble gases with the carbon atom of graphite have been determined, using experimental values of 1 for the adsorption of these gases on graphitized thermal carbon blacks. The corresponding changes in internal energy, entropy and heat capacity have been calculated.The effect of the form and the parameters of the potential function φ of the intermolecular interaction of a monoatomic molecule with the basal face of graphite on the energy φo in the minimum of the potential curve φ(), and on the product o of the specific surface area , and the equilibrium distance between the molecule and the surface o, has been studied. φo and o were determined from experimental values of the Henry adsorption constant 1 measured at different temperatures. From the experimental values of 1 for the adsorption of noble gases, the value of for graphitized thermal carbon black Sterling PT, 2700 (P-33), has been determined. This value of does not essentially depend on the adsorbate and lies within the limits of error of the value, determined for this carbon black by the BET method. When determining from 1, it is necessary to take into account the structure of the solid so as to choose the form of potential φ correctly. Values of o should be determined from the atom-atom potential function of the adsorbate-adsorbent intermolecular interaction. 相似文献
A methoxy group on a styrene double bond directs O2 attack , giving 1,4 addition if the phenyl is , or ene reaction if a CH3 is . If no substituent is , 1,4 attack on the phenyl occurs at a slower rate. 相似文献
The β-chlorovinylphosphines R2PF2)3 (R = C6H5, C6H11) react with Fe(CO)5 yielding compounds of stoichiometry . The crystal structure of one of these (R = C6H11) has been determined from X-ray diffraction data and refined by least-squares to = 0.037 (2313 reflections with > 2.3σ). Crystals are triclinic, space group , = 10.253(5), = 15.590(7), = 9.390(4)Å, α = 99.88(3), β = 103.21(2), γ = 92.02(2)°, = 2. The fluorinated π-allyl group is σ-bonded to one Fe atom and π-bonded to the other. 相似文献