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Showing papers in "Journal of Organic Chemistry in 1995"


Journal ArticleDOI
TL;DR: In this article, a direct procedure for Arylboronic Esters was proposed for a cross-coupling reaction of Alkoxydiboron with Haloarenes.
Abstract: G e o r g T h i e m e V e r l a g K G , R ü d i g e r s t r a ß e 1 4 , 7 0 4 6 9 S t u t t g a r t , G e r m a n y 823 T . I S H I Y A M A , M . M U R A T A , N . M I Y A U R A * ( H O K K A I D O U N I V E R S I T Y , S A P P O R O , J A P A N ) Palladium(0)-Catalyzed Cross-Coupling Reaction of Alkoxydiboron with Haloarenes: A Direct Procedure for Arylboronic Esters J. Org. Chem. 1995, 60, 7508–7510.

1,355 citations


Journal ArticleDOI
TL;DR: In this paper, the synthesis and complete characterization of soluble derivatives of C-60 for applications to physics and biology was described, where the goal of the strategy was to have a "modular" approach in order to be able to easily vary a functional group attached indirectly to the cluster.
Abstract: We describe the synthesis and complete characterization of soluble derivatives of C-60 for applications to physics and biology. The goal of the strategy was to have a ''modular'' approach in order to be able to easily vary a functional group attached indirectly to the cluster. The functionality could be hydrophilic (e.g., histamide) or hydrophobic (e.g., cholestanoxy). The former was prepared for biological studies and the latter for photophysical studies toward improvement of photoinduced electron transfer efficiencies in the fabrication of photodetectors and photodiodes. An important intermediate, a carboxylic acid, was found to be recalcitrant to characterization by the usual mass spectroscopic and elemental analysis techniques. This problem was solved by the use of MALDIMS. The carboxylic acid was easily converted to the key intermediate acid chloride, which in turn was convertible to a large variety of derivatives. Both isomeric forms ([5,6], fulleroid and [6,6], methanofullerene) of the C-61 clusters were prepared. The fulleroid formation could have given rise to a 50:50 mixture of phenyl-over-former pentagon phenyl-over-former hexagon isomers but, remarkably, afforded a 95:5 mixture of these isomers, respectively. The fulleroid and methano-fullerene gave different cyclic voltammograms, with the former being reduced at 34 mV more positive potential than the latter.

1,186 citations






















Journal ArticleDOI
TL;DR: The authors report here the first example of a catalytic asymmetric hydrophosphonylation to imines using lanthanoids-potassium-BINOL heterobimetallic complexes (LnPB, Ln = lanthanoid metal), which gives optically active {alpha}-amino phosphonates in modest to high enantiometric excess.
Abstract: {alpha}-Amino phosphonic acids 3 are interesting compounds in the design of enzyme inhibitors. The concept of mimicking tetrahedral transition states of enzyme-medicated peptide bond hydrolysis previously led to the successful design and synthesis of phosphonamide-containing peptides as a promising new class of proteinase inhibitors. It is not surprising that the absolute configuration of the {alpha}-carbon strongly influences the biological properties of 3. Several methods for the synthesis of optically active {alpha}-aminophosphonic acids have been published. The authors report here the first example of a catalytic asymmetric hydrophosphonylation to imines using lanthanoid-potassium-BINOL heterobimetallic complexes (LnPB, Ln = lanthanoid metal), which gives optically active {alpha}-amino phosphonates in modest to high enantiometric excess. 17 refs., 1 tab.






Journal ArticleDOI
TL;DR: Through a series of kinetic and P-31 NMR experiments, it is demonstrated that a mixture of Pd(OAc)(2) and TPPTS affords spontaneously a palladium(0) complex, through formation of bivalent complex Pd-OAc-(TPPTS)(2), considerably less reactive than the corresponding complex generated from PPh(3).
Abstract: Studies on the sp-sp intermolecular coupling reactions with the palladium water-soluble catalyst prepared in situ from palladium(II) acetate and sulfonated triphenylphosphine P(C6H4-m-SO3Na)(3) (TPPTS) in a homogeneous acetonitrile-water system, without Cu(I) promotor, afford diynes with moderate yields (45-65%). Under the same conditions, the sp(2)-sp coupling of 2-iodophenols or 2-iodoanilines and terminal alkynes followed by intramolecular cyclization gives indolic and furanic products in good yields (60-99%). Under these aqueous conditions, an efficient and short synthesis of eutypine illustrated the synthetic potentiality of the coupling. Furthermore, through a series of kinetic and P-31 NMR experiments, we have demonstrated that a mixture of Pd(OAc)(2) and TPPTS affords spontaneously a palladium(0) complex, through formation of bivalent complex Pd(OAc)(2)-(TPPTS)(2). A detailed mechanism of the reaction has been investigated thoroughly and the pertinent rate constants measured. The resulting palladium(0) complex reacts with phenyl iodide via an oxidative addition. This complex is considerably less reactive than the corresponding complex generated from PPh(3), probably due to steric effects.