Alain Duchêne

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 .

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.

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.

An efficient access to homoallyl and homocinnamyl skeletons using 1-tributylstannyl-4,4-diethoxy-but-1-ene

Abstract The easily prepared and stored 1-tributylstannyl-4,4-diethoxy-but-l-ene reacts like a usual vinyltin (unaffected by the presence of the acetal function) allowing easy transfer of the functionally substituted butenyl unit onto miscellaneous substrates via palladium promoted crosscoupling reactions or after transmetallation with butyllithium or high order cyanocuprates.

Stereoselective access to functionalized β-γ unsaturated acids

Stereoselective synthesis of vinylstannanes bearing a carboxylic acid function was achieved from β-γ alkynoic acids via hydrostannation, stannylcupration or silastannation reactions. Regioselectivity is highly dependent on the nature of the stannylanions used and on protection of the carboxylic acid function.

General access to para-substituted styrenes

A simple and efficient procedure has been developed for the synthesis of organogermanium compounds and styrenes para-substituted with groups containing an atom of the 14th group by one-pot reaction of halogenosilanes, germanes or stannanes, organic halides and magnesium using ultrasound methods.

E- and Z-β-formylvinyl synthons from 1-tributylstannyl-3,3-diethoxy-prop-1-ene via cross coupling with acid chlorides

The easily prepared and stored E-1-tributylstannyl-3,3-diethoxy-prop-1-ene 1E reacts with acyl chlorides in DMF in the presence of PdCl2(MeCN)2 to give the expected 1,4-ketoacetals (E isomers). Similarly cross coupling of 1E with tosyl chloride performed in THF in the presence of Pd(PPh3)4 affords the E-β-diethoxymethylvinylsulphone whose metallation with MeLi, LiBr generates a β-formylvinylanion equivalent with the anionic centre in a cis relationship relative to the diethoxymethyl group.

A novel access to organogermanium compounds

Abstract A simple and efficient procedure has been developed for the synthesis of organogermanium compounds by one-pot reaction of halogenogermanes, organic halides and magnesium under microwave irradiation.