Mohamed Abarbri

BROMINE-MAGNESIUM-EXCHANGE AS A GENERAL TOOL FOR THE PREPARATION OF POLYFUNCTIONAL ARYL AND HETEROARYL MAGNESIUM-REAGENTS

Abstract The scope of the BrMg-exchange reaction for the preparation of polyfunctional aryl and heteroaryl magnesium reagents has been studied. Various functional groups (ester, cyano, bromide) were tolerated in the exchange reaction allowing the preparation of polyfunctional Mg-reagents. Several dibromo- or tribromoheterocycles undergo a chemoselective mono-BrMg exchange leading to highly functionalized heterocycles.

Stannylmetallation of acetylenic acids: a stereoselective access to functionalized α, β- and β, γ-unsaturated acids

Abstract The stereoselective synthesis of vinylstannanes bearing car☐ylic acid function was achieved from acetylenic acids via stannylcupration reaction. In homoallylic series, regioselectivities are highly dependant on the nature of stannylanionids and on the protection of the car☐ylic acid function.

Improvements of TArgeted multiplex mass spectrometry IMaging.

MALDI mass spectrometers have become popular tools for imaging histological sections. Currently this technology is primarily used for imaging naturally occurring molecules. Here we report on the improvement of TArgeted multiplex MS IMaging (TAMSIM) technology. For TAMSIM we attach photocleavable mass tags to antibodies. Staining histological sections is done analogously to standard immunohistochemical procedures with chemiluminescent or fluorescent detection with the sole difference that multiple antibodies each with a distinct mass tag are used in a single reaction. Mass tags are released from their respective antibodies by a laser pulse at 355 nm without added matrix. After scanning, MS images are created for each tag mass. The enhancements of TAMSIM presented here relate to four elements, the use of an improved generation of tags, their conjugation directly to primary antibodies, the comparison of fresh frozen sections with paraffin embedded ones for the TAMSIM imaging technology and finally, the increase of multiplex detection. Sections of healthy human pancreatic tissue were imaged to visualize different specific biomarkers (synaptophysin, chromogranin, insulin, calcitonin, somatostatin) in neuroendocrine cells of Langerhans islets. The aim was to localize these biomarkers on the tissue sections simultaneously.

Domino allylic amination/Sonogashira/heterocyclisation reactions: palladium-catalysed three-component synthesis of pyrroles

Three-component reactions with 3,4-diiodoalk-2-enoic derivatives, primary amines, and terminal alkynes proceeded to give trisubstituted pyrroles in fair to good yields in the presence of palladium and copper catalysts under mild reaction conditions.

SYNTHESIS OF ETHYL (13E)-TRIFLUOROMETHYLRETINOATE AND ITS ANALOGUES BY PALLADIUM-CATALYSED CROSS-COUPLING

Abstract Stereoselective construction of ethyl (13 E )-trifluoromethylretinoate was achieved through two successive Stille reactions. The coupling of ( E )-1,2-bis(tributylstannyl)ethene and ethyl ( Z )-4,4,4-trifluoro-3-iodobut-2-enoate was performed first and followed by iododestannylation. The second step involved another vinyltin which was synthetised by stannylmetallation of the Nigishi dienyne 4c derived from β-ionone. Certain yne analogues were also prepared through Sonogashira coupling with 4c,d and ethyl 5-iodo-3-trifluoromethyl-pent-2,4-dienoate 3 .

A SYNTHETIC APPROACH TO NATURAL DIENAMIDES OF INSECTICIDAL INTEREST

Abstract An efficient synthesis of dienamides of insecticidal interest has been stereoselectively achieved featuring a Stille cross-coupling reaction as the key step.

Stereospecific synthesis of (Z) or (E)-3-methylalk-2-enoic acids

Abstract The palladium catalysed coupling of organozinc or organotin reagents with 3-iodobut-2(or 3)-enoic acid is stereoselective and affords Z (or E )-3-methylalk-2-enoic acids. The method was applied to the synthesis of the E and Z stereoisomers of ocimenones and pseudo-tagetones.

Regioselective Copper-Mediated Synthesis of Thieno[2,3-c]pyrane-7-one, Indolo[2,3-c]pyrane-1-one, and Indolo[3,2-c]pyrane-1-one

In the presence of copper(I) iodide, heteroaromatic β-iodo-α,β-unsaturated carboxylic acid systems opposed to terminal alkyne afford selectively 6-endo-dig cyclization products via a tandem coupling oxacyclization reaction.

Carboxylate‐Directed Tandem Functionalisations of α,β‐Dihaloalkenoic Acids with 1‐Alkynes: A Straightforward Access to (Z)‐Configured, α,β‐Substituted γ‐Alkylidenebutenolides

An easy and mild copper(I)-catalysed lactonisation of readily available (E)-2,3-dihalopropenoic acid derivatives regio- and stereoselectively leads to rarely described (Z)-3-halo-5-ylidene-5H-furan-2-ones. These compounds are subsequently able to undergo classical Pd-catalysed cross-coupling reactions, providing 3-substituted and 3,4-disubstituted 5-ylidene-5H-furan-2-ones

Regio- and selective synthesis of 4,6-disubstituted-2-pyridones

Abstract Palladium catalysed regio- and stereoselective annulation of allenyl stannanes by β-iodo vinylic amides gives good yields of the corresponding 2-pyridones. This annulation probably occurs via a Stille reaction/cyclisation sequence.