Oxidation of furans with dimethyldioxirane. Interception of malealdehyde and related aldehydes via Wittig reactions

Abstract

Unsaturated aldehydes including malealdehyde, generated in acetone by oxidation of furans with dimethyldioxirane, can be trapped efficiently by phosphoranes in Wittig reactions.

Synthesis of γ-Lactones and Ascorbic Acid Analogues by Diastereoselective Hydrogenation of α-Hydroxy-γ-alkylidenebutenolides

“…The configuration of 11 was established by comparison of the 1 H NMR spectroscopic data with those reported in the literature. [22] It seems appropriate to briefly compare the 1 H NMR spectroscopic features of lactones 4, 6, 7, and 8 (Table 2). Thanks to the identical relative configurations of their substituents, lactones 4 all exhibited similar chemical shifts for protons 4-H, 4-HЈ, 3-H, and 5-H. Hydrogen atoms 4-H and 4-HЈ were assigned on the basis of the observed coupling constants (vide supra).…”

“…The configuration of 11 was established by comparison of its 1 H NMR spectroscopic data with those reported in the literature for the (E,Z) and (Z,Z) isomers. [22] The product was obtained as a 2.5:1 mixture of (E,E) and (E,Z) isomers. 1 Synthesis of γ-Alkylidenebutenolides 12a, 12c, and 12d: The synthesis of these compounds has been reported.…”

The Achmatowicz Rearrangement – Oxidative Ring Expansion of Furfuryl Alcohols

“…McKervey and Murray used dimethyldioxirane as oxidizing agent in a preparative manner in the ring fission of various furan structures including furyl alcohols. 74,75 The reagent proved to be an effective inducer of Achmatowicz-type rearrangements and very high conversions were achieved under mild conditions with acetone as the sole side product (Scheme 21). 75 Scheme 21 Dimethyldioxirane as Achmatowicz inducer…”

2-Trimethylsilyloxyfuran

“…Oxidation of TMSOF with dimethyldioxirane (DMDO) followed by ring opening of the resulting hydroxybutenolide with a Wittig reagent furnishes exclusively the (2Z, 4E) monoacid product (eq 40). 95 Ring opening of TMSOF is also achieved by treatment with aryl diazoacetates under rhodium(II)catalysis, affording the corresponding 6-aryl-6-oxo-(2Z, 4E)hexadienoic acids (eq 41 Related Reagents. Several other 2-trialkylsilyloxyfurans have served as building blocks for the synthesis of natural products 28a,b and analogs.…”