Guy Solladié

A re-investigation of resveratrol synthesis by Perkins reaction. Application to the synthesis of aryl cinnamic acids

A re-investigation of resveratrol synthesis by Perkins reaction allowed to improve this method and to determine the configuration of the intermediates. The results were applied to the synthesis of several aryl cinnamic acids for biological evaluation.

A catalytic effect of ZnCl2 during dibal reduction of β-ketosulfoxides.

High asymmetric inductions (>94/6) are obtained upon DIBAL reduction of β-ketosulfoxides in the presence of non-stoichiometric amounts of ZnCl2 (0.5 equiv, to 0.05 equiv.). Intramolecular hydride transfer and new chelated models are proposed to explain the observed stereoselectivity.

A general protocol for the regio high yielding opening of different glycidol derivatives

Abstract Differently protected glycidol derivatives (with Bn, TBDPS, TBS and MPM groups) have been tested for regioselective ring opening with vinylmagnesium bromide in order to obtain useful five-carbon functionalised homoallylic alcohols. Careful choice of the reagents and experimental conditions allowed a general access to important chiral synthons for asymmetric synthesis.

CHIRAL SULFOXIDES IN ASYMMETRIC SYNTHESIS : ENANTIOSELECTIVE SYNTHESIS OF (-)-(5S,7R)-TARCHONANTHUSLACTONE

Abstract The enantioselective synthesis of (−)-(5S,7R)-Tarchonanthuslactone, a substituted δ-lactone isolated from a compositae, is described. The main feature of this short synthesis is the stereoselective reduction of a β,δ-diketosulfoxide affording in 6 steps the chiral central part of the molecule, a syn-1,3-diol unit.

ASYMMETRIC SYNTHESIS OF SYN AND ANTI 1,2-DIOLS FROM DIETHYL OXALATE USING THE STEREOSELECTIVE SULFOXIDE DIRECTED REDUCTION OF 1,2-DIKETONE DERIVATIVES

Abstract A new chiral Wittig reagent, a β-keto-γ-( S )-hydroxy-δ-( R )- p -tolylsulfinyl phosphonate, readily made from ethyl oxalate and stereoselective sulfoxide mediated reduction of the resulting β-ketosulfoxide, was used to prepare enantiomerically pure syn and anti 1,2-diols. This method was applied to the enantioselective synthesis of two acetogenin derivatives, (−)-( R,R )-muricatacin and its epimer (−)-( R,S )-epi-muricatacin.

Stereoselective synthesis towards the C8–C18 subunit of pamamycin-607 induced by a chiral sulfoxide group

Abstract A close precursor of the C8–C18 subunit of pamamycin-607 was prepared by asymmetric synthesis from ethyl butyryl acetate via a chiral β,δ-diketosulfoxide.

1,4 Asymmetric induction in the carbonyl reduction of a γ-ketosulfoxide

Abstract a chiral sulfoxide induced high stereoselectivity in the DIBAL-H reduction of a methyl ketone located in the γ position as a result of a 1,4-asymmetric induction. Addition of a lanthanide triflate or cerium chloride completely reversed the stereoselectivity.

TOTAL SYNTHESIS OF (+)-INDOLIZIDINE 195 B AND (+)-MONOMORINE

Abstract The total synthesis of (+)-Indolizidine 195 B and (+)-Monomorine is described. The formation of the chiral centers was stereocontrolled by chiral sulfoxides.

Wang p-alkoxyphenylsulfoxide as a new linker and Pummerer cleavage strategy in solid-phase preparation of 1,2-diols

Abstract para -Hydroxyphenyl-β-ketosulfide was attached to a Wang resin and oxidised to the corresponding sulfoxide with a N -protonated oxaziridinium trifluoroacetate. Reduction of the β-ketosulfoxides to the corresponding β-hydroxysulfoxides with Dibal-H was shown to be as stereoselective as in solution. Finally it was shown that the Pummerer reaction could be carried out on solid-phase and was a very efficient way to obtain diols that validates the sulfoxide group as a versatile linker for solid-phase chemistry.

Synthesis of (+)-(R)-5-hydroxy-6-hydroxymethyl-7-methoxy-8-methylflavanone

Abstract The synthesis of (+)-( R )-5-hydroxy-6-hydroxymethyl-7-methoxy-8-methylflavanone is described. A new chromylation method of β-ketosulfoxide 9 leading to the Michael acceptor 12 has been developed. Dilithium tetrachlorocuprate was shown to be a very efficient catalyst for the conjugate addition reaction of phenyl magnesium bromide to the α,β-unsaturated sulfoxide 12 . The instability of the obtained adducts 10 represents a limitation in terms of yield. It was confirmed that the natural flavanone leridol does not possess the structure of title compound 1 .