- Regioselective synthesis of (E)-5-(tributylstannylmethylidene)-5H-furan-2- ones and (E)-3-(tributylstannylmethylidene)-3H-isobenzofuran-1-ones: Easy access to γ-alkylidenebutenolide and phthalide skeletons
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Regio- and stereoselective synthesis of γ-alkylidene-butenolides and γ-alkylidenephthalides has been achieved through the palladium-catalysed tandem cross-coupling/cyclisation reactions of tributylstannyl-3-iodopropenoate or the 2-iodo benzoate derivatives with tributyltinacetylene. Iododestannylation occurred with inversion of the configuration of the exocyclic double bond in the case of butenolides, but with retention of configuration for the phthalide. The selectivity observed in the Stille reaction was found to be dependent on the nature of the vinyl or the aryl halide. Georg Thieme Verlag Stuttgart.
- Duchene, Alain,Thibonnet, Jerome,Parrain, Jean-Luc,Anselmi, Elsa,Abarbri, Mohamed
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- Stereoselective and convergent syntheses of retinoic acid and its ester derivatives by the sulfone olefination reaction
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An extensive study on the stereoselective and convergent syntheses of retinoic acid and its ester derivatives utilizing the Julia sulfone olefination reaction has been reported. Various C5 units of the acid 4a, the esters 4b-e from the chemically and biologically important alcohols, and the furanone 6 have been prepared and coupled with the C15 allylic sulfone 3 to give the C20 compounds 10 and 11, which provided all-(E)-retinoic acid (1a), its ester derivatives 1b-e, and the furanone analogue 12b in a highly stereoselective manner after dehydrosulfonation reaction. The Julia olefination reaction of the C5 diester 13 and the C15 allylic sulfone 3 produced the known C20 diacid 15 which underwent stereoselective mono-decarboxylation to provide either 13-(Z)-retinoic acid (2) or all-(E)-retinoic acid (1) depending on the reagent used.
- Jeon, Hye-Sun,Yeo, Jung Eun,Jeong, Young Cheol,Koo, Sangho
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p. 2813 - 2820
(2007/10/03)
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