Synthesis, rearrangements, and fragmentation of ketene mercaptals derived from ketones or β-diketones and carbon disulphide
1974; Elsevier BV; Volume: 30; Issue: 1 Linguagem: Inglês
10.1016/s0040-4020(01)97222-9
ISSN1464-5416
AutoresLars Dalgaard, Lotte Groth Jensen, S.‐O. LAWESSON,
Tópico(s)Organic Chemistry Cycloaddition Reactions
ResumoBy use of the ion pair extraction technique, tetrabutylammonium salts of acetylacetone, benzoylacetone, and dibenzoylmethane were reacted with carbon disulphide to give salts of dithioacids. Alkylation gave dithioesters and ketene mercaptals. A simple procedure for the preparation of 2-diacylmethylene-1,3-dithietanes was found. Cyclisation reactions of some acetylacetone derivatives gave a 1,3-dithiolane, a mercaptothiophene, and a [2.3-b] thienothiophene. Allylic ketene mercaptals derived from acetone, cyclohexanone, acetylacetone, benzoylacetone, and dibenzoylmethane rearranged to α-allyl-dithioesters. Inversion of the migrating allyl group was observed when the ketene mercaptal had a vinylic hydrogen; otherwise retention was found. 3-[(Crotylthio-, methylthio-)methylene] acetylacetone underwent decomposition at 170° to methyl, 1-methyl-allyl sulphide and the "desaurin": 2,4-bis-(diacetyl-methylene)-1, 3-dithietane. By-products in syntheses of the dithioesters and ketene mercaptals included trithiocarbonates, alkylated β-diketones, and compounds formed by reactions of the solvent (CH2Cl2) with β-diketones or their carbon disulphide adducts (1,3-di-thietanes).
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