Iodine(III)-promoted ring expansion of 1-vinylcycloalkanol derivatives: A metal-free approach toward seven-membered rings
ABSTRACT A versatile and metal-free approach for the synthesis of molecules bearing seven- and eight-membered rings is described. The strategy is based on the ring expansion of 1-vinylcycloalkanols (or the corresponding silyl or methyl ether) mediated by the hypervalent iodine reagent HTIB (PhI(OH)OTs). The reaction condition can be easily adjusted to give seven-membered rings bearing different functional groups. A route to medium-ring lactones was also developed.
- ChemInform 08/2008; 39(32). DOI:10.1002/chin.200832063
Article: Chemistry of Polyvalent IodineChemical Reviews 12/2008; 108(12):5299-358. DOI:10.1021/cr800332c · 45.66 Impact Factor
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ABSTRACT: A set of enantiopure carbohydrate mimetics has been synthesized via Lewis acid promoted cyclization of 1,3-dioxolanyl-substituted enol ethers as a crucial new step providing highly functionalized 3,6-dihydro-2H-pyran derivatives. The flexible approach starting from glyceraldehyde-derived nitrone is comprised of only six simple steps smoothly allowing synthetic modifications at the different stages of the sequence. All reactions proceeded with good to excellent stereocontrol and can be performed with either of the two enantiomers.Organic Letters 11/2009; 11(23):5534-7. DOI:10.1021/ol902354f · 6.32 Impact Factor