100884-27-3Relevant articles and documents
Generation and reaction of monocarbonyliodonium ylides: Ester exchange of (Z)-(β-acetoxyvinyl)iodonium salts with lithium ethoxide and synthesis of α,β-epoxy ketones
Ochiai, Masahito,Kitagawa, Yutaka,Yamamoto, Shinji
, p. 11598 - 11604 (2007/10/03)
Reported here for the first time are the generation of monocarbonyliodonium ylides and their alkylidene-transfer reactions to aldehydes yielding α,β-epoxy ketones. Exposure of (Z)-(2-acetoxy-1-decenyl)iodonium bromide, prepared stereoselectively by sodium acetate-catalyzed Michael addition of acetic acid to (1-decynyl)(phenyl)iodonium salt, to EtOLi in THF at -78°C results in ester exchange to generate the monocarbonyliodonium ylide with the liberation of ethyl acetate. 1H NMR measurements indicate that the ylide is stable up to -30°C in THF-d8 but gradually decomposes at -20°C to 1-bromo-2-decanone. The monocarbonyliodonium ylide acts as an alkylidene-transfer agent to carbonyl compounds, and the reaction with aldehydes in THF-DMSO at -30°C gives α,β-epoxy ketones with E-isomers as a major product. With an α,β-unsaturated aldehyde, selective 1,2-addition to the carbonyl group was observed. The relative rates of the alkylidene-transfer reaction of this ylide for a series of ring-substituted benzaldehydes were measured. A Hammett correlation plot with the σ constants of substituents afforded the reaction constant ρ = 2.95 (r = 1.00), which indicates that the monocarbonyliodonium ylide is moderately nucleophilic in nature.
