- Abnormal behaviour of allenylsulfones under Lu's reaction conditions: Synthesis of enantiopure polyfunctionalised cyclopentenes
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Formal [3+2] cycloadditions of 5-alkoxyfuran-2(5H)-ones 1 and 2 with allenylsulfones 3-5, promoted by different nucleophiles, afford 3-alkoxy5-arylsulfonyl-3,3 a,6,6 a-tetrahydro-1Hcyclopenta[c]furan-l-ones in good yields with complete control of both regio- and π-facial selectivity. The incorporation of a sulfinyl group on the furanone ring enhances the reactivity of the furanones and allows the synthesis of optically pure, bicyclic adducts in good yields. Allenylsulfones evolve through a different mechanism to that proposed for allenoates (Lu's reaction) and afford bicyclic adducts in which the sulfonyl group is joined to C-5. This has advantages on the stereochemical control of further reactions leading to enantiomerically pure polyfunctionalised cyclopentenes and cyclopentanes.
- Nunez Jr., Alberto,Rosario Martin,Fraile, Alberto,Garcia Ruano, Jose L.
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scheme or table
p. 5443 - 5453
(2010/10/03)
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