Tetrahydrofurane-3-one

The formation of the oxepanes (160) and (161) by treatment of 2,2,5,5-tetramethyl-tetrahydrofuran-3-one with diazomethane is included in the present category although it is probable that the reaction proceeds by two separate ring expansion steps (cf. equation 47) as shown in Scheme 32 (72HC(26)l). Photolytic C—O bond cleavage of a dihydrofuran... 

Bamford-Stevens reaction of the tosylhydrazones of the readily available tetrahydrofuran-3-ones provides a useful synthesis of 2,3-dihydrofurans which may be dehydrogenated to furans with 2,3-dichloro-5,6-dicyano-l,4-benzoquinone (66CJC1083). Tetrahydrofuran-2-ones (y-butyrolactones) may be alkylated in the 3-position with LDA and an alkyl halide. The products on reaction with phenyl selenylchloride and LDA, and subsequent oxidation, yield 3-alkylfuran-2(5//)-ones reducible with DIBAL to furans (75JOC542). 

Intramolecular addition of acyl radicals to enoates proceeds in high yields. The acyl radicals are generated conveniently from acyl selenides. The application of this methodology in the stereoselective synthesis of cis-2,5-disubstituted tetrahydrofuran-3-ones is illustrated [95TL31],... 

Reductive cleavage of 2-tosyl-2-aza-7-oxabicyclo[2.2.1]heptan-5-ones by Et3SiH leads to either piperidine derivatives or tetrahydrofuran-3-ones, depending on the Lewis acid catalyst. Cleavage of the C(l)—O bond is favored by the presence of TiCU, whereas C(l)—N bond cleavage facilitated by SnCU or BF3 OEt2. °... 

Acyl radical cyclization of ) -alkoxyacrylates provides five-, six-, and seven-mem bered oxacyclic ketones with high stereoselectivity [45], In a key step in the synthesis of (—)-kumausallene (55) by Evans, the tetrahydrofuran-3-one 69 was obtained stereoselectively from the acyl selenide 68 [46] (Scheme 24). 

Intramolecular (2+2)-cycloaddition within the dioxenones (83) results in the formation of the adducts (84) and (85) in the ratios shown. The adducts can be opened by thermal means to provide routes to tetrahydrofuran-3-ones and tetrahydropyran-4-ones. Intramolecular cycioaddition of the dioxenone (86) results in the formation of the diastereoisomeric mixture of (87) and (88) in a... 

In the initial period of our synthetic efforts on the construction of the A/B ring equivalents, we had prepared two functionalized tetrahydrofuran-3-ones 62 and 64 from 2 (Scheme 7). We experienced at that time much difficulty in the C7-C8 bond formation (the eremantholide numbering) by means of an intramolecular aldol (62 to 63) or an intramolecular Horner-Emmons (64 to 65) reaction. After throughout investigations examined using theses and related substrates, we finally abandoned the A/B ring construction by means of these base-mediated "polar" carbon-carbon bond forming reactions. 

Berhn S, Ericsson C, Engman L (2003) Radical caibonylation/reductive cyclization for the construction of tetrahydrofuran-3-ones and pyrrolidin-3-ones. J Org Chem 68 8386-8396... 

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