Showing papers in "Bulletin of the Chemical Society of Japan in 1988"
TL;DR: An overview of the duality of function of organosulfones as nucleophiles in basic media and electrophiles in Lewis acidic media, a change of reactivity for which they have been dubbed "chemical chameleons" is presented in this article.
Abstract: An overview of the duality of function of organosulfones as nucleophiles in basic media and electrophiles in Lewis acidic media, a change of reactivity for which they have been dubbed “chemical chameleons,” is presented. In the first phase, transition metal catalysts activate allyl sulfones towards displacements. Use of palladium, molybdenum, and nickel catalysts allow stabilized anions to effect displacement; copper catalysts allow non-stabilized nucleophiles to be used. The use of the anion stabilizing and leaving group abilities of sulfones created a novel three carbon intercalation and a novel cyclocontraction-spiroannulation in which β-hydroxy sulfones participate in a Lewis acid catalyzed pinacol rearrangement. The lability of allyl and tertiary sulfones towards Lewis acids creates a wide array of electrophilic reactions such as Friedel–Crafts type cyclizations, intermolecular alkylations with organoalanes and enol silyl ethers, and ring expansions. The ability to design novel reagents for synthesis...
197 citations
TL;DR: In this paper, the catalytic activities of perovskite-type mixed oxides (LnBO3 and Ln0.8Sr0.2CoO3, Ln=rare earth (lanthanoid) elements, B=3d transition metals) for the oxidation of propane and methanol have been studied comparatively.
Abstract: The catalytic activities of perovskite-type mixed oxides (LnBO3 and Ln0.8Sr0.2CoO3, Ln=rare-earth (lanthanoid) elements, B=3d transition metals) for the oxidation of propane and methanol have been studied comparatively. It has been found that the catalytic activities of LnBO3 were principally determined by the B-site elements and were similar to those of the corresponding oxides of the B-site elements. The roles of the rare-earth ions of the A-site were secondary as long as they were trivalent. Upon the partial replacement of Ln3+ by Sr2+, the catalytic activities of LnCoO3 increased several times, the magnitude of the increase being similar among all the rare-earth ions. These results demonstrate that the kind and the valence of a B-site metal are of primary importance for the control of the catalytic activity for oxidation, almost regardless of the kind of trivalent rare-earth elements at the A-site.
174 citations
TL;DR: N,N′-Dialkyl-1,4-benzenedicarboxamides melt with anomalously small enthalpy changes The 1,3-analogs behave similarly but at lower temperatures.
Abstract: N,N′-Dialkyl-1,4-benzenedicarboxamides melt with anomalously small enthalpy changes The 1,3-analogs behave similarly but at lower temperatures These observations provide a clue to design novel me
125 citations
TL;DR: In this article, the helium isotope ratios of terrestrial natural gas samples were measured using a high-precision mass spectrometer and an ultra-high-vacuum purification line.
Abstract: Helium isotope ratios of terrestrial natural gas samples were measured using a high-precision mass spectrometer and an ultrahigh-vacuum purification line. The line is equipped with a charcoal trap held at 40 K using a helium expansion refrigerating machine. To avoid interference, Ne was completely separated from He by the trap before the gas was admitted to the mass spectrometer. Ion beams of 3He and 4He were measured at the same time by a double collector system. A resolving power of about 550 at the 5% level of the peak height was attained for the complete separation of 3He ions from those of HD and H3. Precision and reproducibility of the helium isotope ratio were less than 1%, examined by repeated measurements of an air standard. Accuracy of the ratio was checked by comparing observed data with reports in the literature.
122 citations
TL;DR: In this paper, synthetic hydrotalcite, Mg6Al2(OH)16CO3·4H2O, and its analogues were synthesized, heat-treated at 773 K, and used as catalysts for the title reaction to form methyl vinyl ketone (MVK) at 673 K.
Abstract: Synthetic hydrotalcite, Mg6Al2(OH)16CO3·4H2O, and its analogues were synthesized, heat-treated at 773 K, and used as catalysts for the title reaction to form methyl vinyl ketone (MVK) at 673 K. MVK was formed over all the catalysts examined, the highest MVK yield (20% on acetone basis) being found over the heat-treated hydrotalcite.
120 citations
TL;DR: In this article, the synthesis of isoflavone derivatives by means of palladium-catalyzed cross-coupling reaction between 3-bromochromones and arylboronic acids or its butyl esters is described.
Abstract: The synthesis of isoflavone derivatives by means of palladium-catalyzed cross-coupling reaction between 3-bromochromones and arylboronic acids or its butyl esters is described.
118 citations
TL;DR: In this article, the effect of variation of structural factors on the spin exchange interaction between copper(II) centers in dialkoxo-bridged dinuclear copper complexes were studied by the ab initio MO method with UHF formalism.
Abstract: The effect of variation of structural factors on the spin-exchange interaction between copper(II) centers in dialkoxo-bridged dinuclear copper complexes were studied by the ab initio MO method with UHF formalism. The calculations were performed on di-μ-methoxotetraamminedicopper(II). The J-values were obtained as functions of Cu–O–Cu angle, dihedral angle between two coordination planes, planarity of bonds on the bridging oxygens, tetrahedral distortion of coordination planes, and the tilt of O–C bond from the O–O axis. The results demonstrated that the Cu–O–Cu angle most effectively affect the J-value but the other factors are less effective.
111 citations
TL;DR: In this paper, the Dioctadecyldimethylammonium bromide monohydrate (2C18N+2C1Br−·H2O) was crystallized from its solution in chloroform and hexane.
Abstract: Dioctadecyldimethylammonium bromide monohydrate (2C18N+2C1Br−·H2O), C38H80NBr·H2O, was crystallized from its solution in chloroform and hexane. The crystals are triclinic with the space group P\bar1, Z=2, a (normal to the bilayer surface)=3.811(2), b=0.7890(2), c=0.7418(2) nm, α=104.37(3), β=103.06(4), and γ=74.93(3)°. The structure was solved by the direct method and refined by the block-diagonal least-squares procedure: R=0.08 for 3121 observed reflections. The crystal structure consists of bimolecular layers stacking regularly along the a-direction. The two amphiphile molecules in the unit cell are related by centrosymmetry and pack tail to tail in a bilayer structure with tilting hydrocarbon chains by about 45° to the bilayer surface. The packing cross section per molecule in the layer plane is 0.567 nm2. The hydrocarbon chains pack with an triclinic (T//) subcell with dimensions of as=0.42, bs=0.49, cs=0.26 nm, αs=88, βs=104, and γs=111°. One of the two alkyl chains bends near the nitrogen atom and c...
105 citations
TL;DR: In this paper, a thermochromic derivative of salicylideneaniline, N,N′-bis(salicylide)-p-phenylenediamine (BSP), has been prepared and subjected to structural and optical studies in the crystalline state.
Abstract: A thermochromic derivative of salicylideneaniline, N,N′-bis(salicylidene)-p-phenylenediamine (BSP), has been prepared and subjected to structural and optical studies in the crystalline state. An X-ray crystallographic analysis has shown that the molecules are planar and are stacked in a parallel fashion to form one-dimensional columns. The interplanar spacing has been found to be quite short, suggesting the existence of an intermolecular charge-transfer interaction. The molecule contains fairly short O–H··· N hydrogen bonds, the strength of which is manifested in an OH stretching absorption band in the infrared region, showing considerable broadening and a low-frequency shift. The BSP crystals are remarkably thermochromic, and visible absorption and emission spectral changes with temperature have been interpreted in terms of an intramolecular proton transfer from the hydroxyl oxygen to imine nitrogen through the O–H··· N hydrogen bond. The emission spectra have also been examined under high pressures.
104 citations
TL;DR: The first isolation and structure elucidation of four sulfur-containing indole phytoalexins from Chinese cabbage inoculated with Pseudomonas cichorii is described in this paper.
Abstract: The first isolation and structure elucidation of four sulfur-containing indole phytoalexins from Chinese cabbage inoculated with Pseudomonas cichorii are described.
102 citations
TL;DR: In this paper, two highly enantioselective methods for hydrocyanation of aldehydes were developed by using chiral alkoxytitanium reagents.
Abstract: Two highly enantioselective methods for hydrocyanation of aldehydes were developed by using chiral alkoxytitanium reagents. Treatment of benzaldehyde with cyanotrimethylsilane in the presence of a ...
TL;DR: The reaction of aromatic amines with benzyltrimethylammonium dichloroiodate(1) in dichloromethane-methanol in the presence of calcium carbonate powder for several hours at room temperature gave se...
Abstract: The reaction of aromatic amines with benzyltrimethylammonium dichloroiodate(1—) in dichloromethane–methanol in the presence of calcium carbonate powder for several hours at room temperature gave se...
TL;DR: In this article, the conditions for obtaining the electrocapillary curves of the dilauroylphosphatidylcholine (DLPC) monolayer formed at the polarized nitrobenzene-water interface have been studied using the pendant drop method.
Abstract: The conditions for obtaining the electrocapillary curves of the dilauroylphosphatidylcholine (DLPC) monolayer formed at the polarized nitrobenzene–water interface have been studied using the pendant drop method. To facilitate the measurement, the system for the interfacial tension measurement, including the computer software for the data handling, has been developed based on digital image processing of the video image of a pendant drop. The 95% confidence interval of the measured interfacial tension value was ±0.06 mN m−1. The time required to measure an electrocapillary curve with 30 points was 30 min, while the time necessary to convert the image data to the interfacial tension was 1 min. The potential drop across the monolayer has been demonstrated to influence the stability of the monolayer strongly. The DLPC markedly lowered the interfacial tension by forming a stable monolayer when the interface was polarized so that the aqueous phase has a negative potential with respect to the nitrobenzene phase. ...
TL;DR: In this article, the asymmetric ring opening of meso-2,3-disubstituted oxiranes with thiols, aniline, and trimethylsilyl azide was studied by the use of metal(II) d-tartrates as heterogeneous chiral Lewis acid catalysts.
Abstract: The asymmetric ring opening of meso-2,3-disubstituted oxiranes with thiols, aniline, and trimethylsilyl azide was studied by the use of metal(II) d-tartrates as heterogeneous chiral Lewis acid catalysts. The enantioselectivity varied widely with the combination of oxirane, nucleophile, and metal(II) d-tartrate, and Zn(II) d-tartrate gave the best enantioselectivity in the respective reactions of 1,2-epoxycyclohexane with 1-butanethiol, aniline, and trimethylsilyl azide to afford the corresponding adducts in 85, 58, and 42% ee, respectively. Furthermore, the kinetic resolution of racemic oxiranes with thiols catalyzed by Zn(II) d-tartrate was studied.
TL;DR: In this article, the first-neighbor structure of pure N,N-dimethylformamide (DMF) and acetonitrile (AN) was investigated by X-ray diffraction at 25 °C.
Abstract: Liquid structures of pure N,N-dimethylformamide (DMF) and acetonitrile (AN) as well as of their 1 : 1 molar mixture were investigated by X-ray diffraction at 25 °C. The careful reinvestigation of pure DMF led to a good reproducibility of the previous result. Slight deviations in the structural parameters are discussed and a detailed parameter table is reported. A simple model in which each AN molecule has 2 neighbors at an average distance of 330 pm describes the more ordered first neighbor structure of pure AN. The main interaction forming the structure is of dipole–dipole type, in agreement with previous findings. In the 1 : 1 molar mixture a dipole–dipole model also leads to a satisfactory description of the first neighbor structure. The preferred orientation is that with dipoles in the antiparallel position. A central DMF molecule has 1.75 neighboring AN molecules in average at a distance of 316 pm. The same stands for DMF around AN. No evidence for other kinds of interaction, e.g., weak H-bond type i...
TL;DR: Barium hexaaluminate, BaO·6Al2O3, exhibited excellent heat resistance in maintaining a large surface area as mentioned in this paper, and was a superior process to that from mixtures of BaCO3γ-Al 2O3.
Abstract: Barium hexaaluminate, BaO·6Al2O3, exhibited excellent heat resistance in maintaining a large surface area. Preparation from hydrolysis of metal alkoxides was a superior process in deriving the large surface area of BaO·6Al2O3, to that from mixtures of BaCO3⁄γ-Al2O3. Direct formation of BaO·6Al2O3 phase at low temperature plays the key role in retaining the fine particle size. The amount of water added for hydrolysis and the aging period of hydrolyzed precursors strongly influenced the surface area of alkoxide-derived BaO·6Al2O3. These effects of the preparation conditions originated from the difference in microstructure and chemical structure of the hydrolyzed precursors. Monodispersed fine precursor particles with high oxide content generated large surface area BaO·6Al2O3.
TL;DR: In this paper, a method for preparation of sterically hindered chiral binaphthol derivatives has been described which involves the intramolecular 1,3-rearrangement of bis(trialkylsilyl ether) of chiral 3,3′-dibromo-1,1′-bi-2-naphthols with t-BuLi.
Abstract: A highly effective method for preparation of a variety of sterically hindered chiral binaphthol derivatives has been described which involves the intramolecular 1,3-rearrangement of bis(trialkylsilyl ether) of chiral 3,3′-dibromo-1,1′-bi-2-naphthol with t-BuLi.
TL;DR: In this paper, the cyanation of chlorobenzene catalyzed by Ni(PPh3)n was examined with various MCN (M=K, Na) -solvent systems by three procedures in order to clarify the conditions under which the reaction occurs.
Abstract: The cyanation of chlorobenzene catalyzed by Ni(PPh3)n, which was generated in situ from NiBr2(PPh3)2–Zn–PPh3(Ni : Zn : P=1 : 3 : 2 molar ratio), was at first examined with various MCN (M=K, Na)–solvent systems by three procedures in order to clarify the conditions under which the reaction occurs. The effects of the systems and the procedures on the reaction were remarkable. It was observed that the cyanide ion has an inhibitory action on both the reduction of Ni(II) and the oxidative addition of the halide to Ni(0). However, when such MCN–dipolar aprotic solvent systems as KCN–HMPA, KCN or NaCN–MeCN, which give low cyanide concentrations, were used, the reaction readily took place at 50–60 °C without reducing Ni(II) prior to the addition of MCN and adding MCN slowly. Various Y-substituted chlorobenzenes, except for those with Y=o-Cl, o-CN, and m-NO2, were cyanated to give the corresponding nitriles in fair to good yields. NiBr2–PPh3 can be used in place of NiBr2(PPh3)2 if MCN is added after reduction. In ...
TL;DR: In this paper, photooxidations of the evaporated films of rubrene, naphthacene, and pentacene were investigated by means of X-ray photoelectron spectroscopy.
Abstract: Photooxidations of the evaporated films of rubrene, naphthacene, and pentacene were investigated by means of X-ray photoelectron spectroscopy. A rubrene film was found to be photooxidized far more easily than a naphthacene film although the molecules of rubrene and naphthacene in solution are known to be almost equally reactive for photooxidation. Although pentacene is photooxidized very easily in solution, the oxidation rate of a pentacene film was little enhanced by the light irradiation. Discussion is given on these behaviors of the evaporated films by considering the molecular packing in the solid state and the mechanism of photooxidation.
TL;DR: Platinum particles were prepared by reducing the hydrogen hexachloroplatinate extracted in organic solvents from an aqueous solution by these extractants:dioctadecyldimethylammonium chloride (DDAC), trioctylmethylamptonium chloride(TMAC), and trioctylonphosphine oxide(TOPO).
Abstract: Platinum particles were prepared by reducing the hydrogen hexachloroplatinate extracted in organic solvents from an aqueous solution by these extractants:dioctadecyldimethylammonium chloride(DDAC), trioctylmethylammonium chloride(TMAC), and trioctylphosphine oxide(TOPO). The extraction ratio of platinum(IV) increased in chloroform, isobutyl methyl ketone, and cyclohexane with an increase in the concentrations of the extractants, and then approached a constant state. The extracts were reduced by formaldehyde or benzaldehyde in the presence of water and a base (sodium hydroxide or triethylamine) for several hours at 65 °C. The platinum particles obtained in chloroform and isobutyl methyl ketone were very stable; their diameters were 15–25 A.
TL;DR: In this article, a new attempt of utilizing solid acid to the cross aldol reaction of silyl enol ethers with aldehydes or acetals has been investigated.
Abstract: A new attempt of utilizing solid acid to the cross aldol reaction of silyl enol ethers with aldehydes or acetals has been investigated. Among solid acids employed, the reaction is promoted most effectively by a catalytic amount of aluminium ion-exchanged montmorillonite (Al-Mont). Simple diastereoselection is significantly sensitive to the nature of the reaction solvent used in the Al-Mont-catalyzed reaction. When the aluminium ions in Al-Mont were replaced by protons or titanium ions in order to investigate the cation effect, almost the same results were observed on simple diastereoselectivity and diastereofacial selectivity. This fact suggests that the metal cations in montmorillonite do not work as Lewis acid in the present aldol reaction. The acid catalysis of montmorillonite in the present aldol reaction is discussed in comparison with the catalytic behavior of some homogeneous acids.
TL;DR: In this article, thermal stabilities of the colored forms at 80°C and photochemical fatigue resistances against coloration-discoloration cycles were measured in PMMA thin film, using 14 derivatives of fulgide with different heterocyclic structures.
Abstract: Thermal stabilities of the colored forms at 80°C and photochemical fatigue resistances against coloration–discoloration cycles were measured in PMMA thin film, using 14 derivatives of fulgide with different heterocyclic structures. The indolyl (12), oxazolyl (13), and thiazolyl (14) derivatives showed very low thermal degradabilities (TD≤1.5%/day) while 12 and pyrazolyl derivative (9) showed low photochemical fatigues (PF≤0.2%/cycle), as compared with the furyl (1), thienyl (2), and pyrrolyl (3) derivatives. However, many of them featured low photo-responsiveness and low absorptivities for coloration on UV irradiation.
TL;DR: The crystal structure of phenanthrene:picric acid molecular complex was determined by X-ray crystal analysis as mentioned in this paper, showing that the intramolecular hydrogen bonding exists in a picric acid.
Abstract: The crystal structure of phenanthrene:picric acid molecular complex was determined by X-ray crystal analysis. Phenanthrene and picric acid molecules are stacked alternately along the c-axis, making their molecular planes parallel to each other. The intramolecular hydrogen bonding exists in a picric acid.
TL;DR: In this article, aldehydes with 2-propanol were reduced by catalysis with hydrous zirconium oxide to give the corresponding alcohols, and the reduction was carried out with primary, secondary, or tertiary alcohols and only secondary alcohols served as hydrogen donors.
Abstract: Reduction of aldehydes with 2-propanol proceeded efficiently by catalysis with hydrous zirconium oxide to give the corresponding alcohols. Most ketones also were reduced efficiently, but conjugated or sterically hindered ketones resisted the reduction. The reduction was carried out with primary, secondary, or tertiary alcohols, and only secondary alcohols served as hydrogen donors. Kinetic experiments have indicated that the reaction rate is of first-order dependence on each of the concentrations of the carbonyl compound, 2-propanol, and the catalyst. An observation of the primary isotope effect has suggested that a step of hydride transfer from absorbed 2-propanol to absorbed carbonyl compound constitutes the rate-determining step for the reduction.
TL;DR: In this paper, the ligand field band due to the copper(II) ion bound to the N2O2-site is at 18.5×103−19.2×103 cm−1 for [CuLn(fsapn)(H2O)4]-NO3, which are higher frequencies than those of the mononuclear complexes.
Abstract: Heterometal binuclear complexes, [CuLn(fsaen)(H2O)n](NO3) (Ln=La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, or Lu; n=4–5) and [CuLn(fsapn)(H2O)4](NO3) (Ln=La, Pr, Nd, Sm, Eu, Gd, Tb, or Dy) have been synthesized and characterized, where H4fsaen and H4fsapn denote N,N′-bis(3-carboxysalicylidene)ethylenediamine and N,N′-bis(3-carboxysalicylidene)-1,2-propanediamine, respectively. The ligand field band due to the copper(II) ion bound to the N2O2-site is at 18.5×103–19.5×103 cm−1 for [CuLn(fsaen)(H2O)n](NO3) and 18.4×103–19.2×103 cm−1 for [CuLn(fsapn)(H2O)4](NO3), which are higher frequencies than those of the mononuclear complexes, [Cu(H2fsaen)](H2O)0.5 and [Cu(H2fsapn)](H2O)0.5 (18.3×103 and 18.4×103 cm−1, respectively). When the complexes are dissolved in pyridine (Py), dimethyl sulfoxide (DMSO), or N,N-dimethylformamide (DMF), the d–d band frequency decreases in the order of the solvent DMSO>DMF>Py for the binuclear complexes, whereas it decreases in the order of DMF>DMSO>Py for the mononuclear complexe...
TL;DR: In this article, the design of tailor-made specific catalysts for a given organic reaction was investigated, and Dibenzamide or N-benzoylbenzenesulfonamide, transition state analogs of benzoic anhydride on transacylation, was found to act as a template upon aluminium ion-doped silica gel and to imprint specific adsorption sites, "footprints", on the surface.
Abstract: The design of tailor-made specific catalysts for a given organic reaction was investigated. Dibenzamide or N-benzoylbenzenesulfonamide, transition state analogs of benzoic anhydride on transacylation, was found to act as a template upon aluminium ion-doped silica gel and to imprint specific adsorption sites, “footprints,” on the surface. The footprints were particular Lewis acid sites with a complementary structure to the template. They demonstrated an enzyme-like specific catalytic function on the butanolysis of benzoic anhydride through their specific affinities for substrate molecules in the transition state.
TL;DR: In this article, the interlayer surface of layered polysilicic acids (H-magadiite and H-kenyaite) were silylated by reaction with diphenylmethylchlorosilane.
Abstract: Silanol groups on the interlayer surface of layered polysilicic acids (H-magadiite and H-kenyaite) were silylated by reaction with diphenylmethylchlorosilane. Dodecyltrimethylammonium magadiite and kenyaite intercalation compounds were used as the intermediates for the conversion. The interlayer modification was confirmed by XRD, IR, 29Si-MAS NMR and elemental analysis.
TL;DR: In this paper, the transfer free energies of I2, ΔGt°(I2), as obtained from solubility measurements of I 2 in the solvents, were analyzed in the light of the TATB reference electrolyte assumption.
Abstract: Standard potentials of I3−/I− and I2/I3− redox couples relative to that of aqueous saturated calomel reference electrode SCE (W), ESCE(w) have been determined in propylene carbonate (PC), N,N-dimethylformamide (DMF), acetonitrile (ACN), and their binary mixtures at 25 °C from potentiometric measurements. The results helped evaluate the standard potentials of the redox couple I2/I− relative to ESCE(w) as well as the related formation constant (Kf) of I3− in these solvent systems. The solvent effects on the formation equilibrium I2+I−\ightleftharpoonsI3− were analyzed in the light of the transfer free energies of I2, ΔGt°(I2), as obtained from solubility measurements of I2 in the solvents, that of I−, ΔGt°(I−), as obtained earlier by use of the widely used TATB reference electrolyte assumption and that of I3−, ΔGt°(I3−), as obtained by subtracting these two contributions from the respective transfer free energies of formation equilibrium in the mixed solvents relative to a chosen reference solvent in each s...
TL;DR: The double-decker 3A was shown to have electron-deficient dianion and a porphyrinate monoanion radical in this paper, and its constitution was proved by UV/VIS, IR, 1H NMR, ESR, ENDOR, and mass spectra.
Abstract: Reaction of tris(2,4-pentanedionato)yttrium(III) with octaethylporhyrin, H2oep in refluxing 1,2,4-trichlorobenzene (TCB) produces a trace (2%) of the double-decker, Y(oep)2 (3A) besides major amounts (72%) of the yttrium(III) monoporphyrinate, Y(oep)(acac) which are separated by chromatography. Appreciable yields of Y(oep)2 (3A) (25%) are obtained from dilithium octaethylporphyrinate, Li2(oep), formed in situ and Y(oep)(acac) in refluxing TCB. The constitution of the double-decker 3A is proved by UV/VIS, IR, 1H NMR, ESR, ENDOR, and mass spectra. The well-defined composition Y(oep)2 requires that one of the porphyrin rings is electron-deficient, i.e. the charge of the YIII ion is compensated by the normal porphyrinate dianion and a porphyrinate monoanion radical. The magnetic moment in the solid state, μeff=1.5 B.M. (5–100 K), demonstrates the radical nature of 3A as well. Under the time resolution of the methods used, the unpaired electron is delocalized between the two porphyrin rings. The wavenumber of ...
TL;DR: In this paper, a review of the control of regio- and stereochemistry which is now possible by the use of the recently introduced haloacetal and the related halosilyl ether cyclizations, starting from a cyclohexenol or a cyclopentenol.
Abstract: This article presents a review of the control of regio- and stereochemistry which is now possible by the use of the recently introduced haloacetal and the related halosilyl ether cyclizations, starting from a cyclohexenol or a cyclopentenol. The hydroxyl group is the control element which permits the addition of two carbon chains to the double bond of the allylic alcohol system, with complete regiospecificity and stereospecificity at the near end of the double bond, and with complete regiospecificity and high stereoselectivity at the far end of the bond. Examples of the use of the new methodology from the field of alkaloid, steroid and prostaglandin synthesis are given.