20854-56-2Relevant academic research and scientific papers
Pd-catalyzed atom-efficient cross-coupling of triarylbismuth reagents with protecting group-free iodophenylmethanols: Synthesis of biarylmethanols
Meka, Suresh,Rao, Maddali L. N.
supporting information, (2020/02/11)
An atom-efficient procedure for the synthesis of functionalized biarylmethanols via the Pd-catalyzed cross-coupling reactions of differently functionalized iodophenylmethanols and triarylbismuth reagents is described. This protecting group-free direct couplings of 2-, 3- or 4-iodophenylmethanols with triarylbismuth reagents afforded biarylmethanols in good to high yields.
Studies on Pd/NiFe2O4 catalyzed ligand-free Suzuki reaction in aqueous phase: Synthesis of biaryls, terphenyls and polyaryls
Borhade, Sanjay R.,Waghmode, Suresh B.
experimental part, p. 310 - 319 (2011/06/18)
Palladium supported on nickel ferrite (Pd/NiF2O4) was found to be a highly active catalyst for the Suzuki coupling reaction between various aryl halides and arylboronic acids. The reaction gave excellent yields (70-98%) under ligand free conditions in a 1:1 DMF/H2O solvent mixture, in short reaction times (10-60 min). The catalyst could be recovered easily by applying an external magnetic field. The polyaryls were similarly synthesized.
Studies on phosphine free Pd-salen complexes as effective catalysts for aqueous Suzuki reaction
Borhade, Sanjay R.,Waghmode, Suresh B.
experimental part, p. 565 - 572 (2010/12/25)
Palladium complexes of the salen ligands, N,N'-bis(salicylidene)- ethylenediamine and N,N'-bis(salicylidene)-1,.-phenylenediamine have been explored for their catalytic activity in a phosphine-free aqueous Suzuki reaction. The various reaction parameters have been systematically optimized with respect to various solvents, bases, temperatures and Pd concentrations. The studies conclude that 1:1 DMF to water solvent ratio, Na2CO 3 as base and 0.5 mo1% of palladium at 90°C is apt for Suzuki reactions. Rapid transformation of substituted aryl iodides and aryl bromides into corresponding biaryls has been observed with excellent yield ranging from 70-86%, under optimized conditions.
Synthesis and applications of tert-alkoxysiloxane linkers in solid-phase chemistry
Meloni, Marco M.,White, Peter D.,Armour, Duncan,Brown, Richard C.D.
, p. 299 - 311 (2007/10/03)
Straightforward syntheses of two tert-alkoxysilyl chloride functionalised resins 3 and 31 that allow facile attachment of 1°, 2°, 3° alcohols and phenols to the solid-phase have been achieved. Resin 3 displayed useful loading levels (0.7 mmol/g), and it was stable to storage in activated form. Siloxanes from reaction of 3 with alcohols and phenols were compatible with a variety of reaction conditions commonly used in solid-phase synthesis.
An enzyme-labile safety catch linker for synthesis on a soluble polymeric support
Grether, Uwe,Waldmann, Herbert
, p. 959 - 971 (2007/10/03)
The development of new and broadly applicable linker groups which are stable under a variety of reaction conditions and allow release of the desired products from the solid support under very mild conditions is of great interest in organic synthesis and combinatorial chemistry. We describe an enzyme-labile safety-catch linker which releases alcohols and amines through i) enzymatic cleavage of an amino group and ii)subsequent lactam formation. The linker group was investigated on different polymeric supports: TentaGel, PEGA, CPG-beads and the soluble polymer POE-6000. From these linker-polymer conjugates 2-methoxy-5-nitrobenzyl alcohol was released by penicillin G acylase catalysed cleavage of a phenylacetamide and attack of the liberated benzylamine on the neighbouring ester group in ortho position. The model study revealed that only in the case of soluble POE-6000 conjugate high yields for the cleavage could be achieved. In the case of the other solid supports the enzyme does not have access to the interior of the polymer matrix. The application of the POE-6000 linker conjugate was investigated for various esters in Pd0-catalysed Heck-Suzuki- and Sonogashira reactions as well as in a Mitsunobu reaction and cycloadditions. These studies proved that the linker is stable under a broad variety of reaction conditions and that the enzymatic method allows for release of the desired product alcohols under extremely mild conditions at pH 7 and 37°C. In addition, the enzymatic reaction proceeds with complete chemoselectivity, that is other esters or amides are not attacked by the biocatalyst. In addition to alcohols amines can also be cleaved by means of the enzyme-initiated two-step process. In these cases the higher stability of amides as compared to esters requires warming to 60°C to induce cyclization and release of the desired product.
An enzyme-labile safety catch linker for combinatorial synthesis on a soluble polymeric support
Grether, Uwe,Waldmann, Herbert
, p. 1629 - 1632 (2007/10/03)
An enzyme-initiated cyclization allows the release of different target molecules from a soluble polymeric support (see picture) under mild conditions (pH 7, 37°C) and in high yield. X = O, NH, NR.
Pd-mediated C-C and C-S bond formation on solid support: A scope and limitations study
Wendeborn, Sebastian,Berteina, Sabine,Brill, Wolfgang K.-D.,De Mesmaeker, Alain
, p. 671 - 675 (2007/10/03)
The scope and limitations of Pd(0)-mediated coupling reactions between aromatic halides linked to a polystyrene resin and boronic acid derivatives (Suzuki coupling), aromatic and vinylic tin compounds (Stille coupling), as well as thiols are reported. For all reactions, conditions were optimized and evaluated with various reagents. In many cases, upon cleavage from the solid support, products were obtained in excellent yields. In most cases, the optimized reaction conditions are superior to those previously reported in the literature.
