Ktionen (I) ute hamoLoga&d to enonu z by aLky.tcuing livukoductivn 06 R3 I the condevuation _ pmduotn 2 (dehived @urn 1 and tony&ntihyL i.mcyanLdel, @.?tv~ed by acid catalyzed hydn_okyhA. a,B-Unsaturated carbonyl compounds (enones) are real workhorses in organic synthesis. Among the most important areas of application are: Michael reactions, 2a and related Robinson (ring) annulations2b and hydrocyanations, 3. Diels-Alder cycloadditions, 2c and heterodiene syntheses.4 The value of these reactions has firmly been established, particularly in the field of natural product synthesis. Although several useful methods are available to prepare a,&unsaturated carbonyl compounds, no general method covers all different types of enones. 5 Thus, it is not surprising that new methods are reported regularly.6 1 2 We report a new synthesis of a,&unsaturated ketones, with the overall characteristics of Eq I. In a formal sense, this conversion of ketones can be seen as a replacement of OH of enolized 1 by an acyl group. The separate steps of this process are given in Eq II in the _ heading of the Table, and are described in the following. Recently, two methods have been developed in our laboratory to convert aldehydes and ketones to unsaturated isocyano sulfones 4 with the use of tosylmethyl isocyanide (TosMIC, 3)! _ So far, only Michael addition-type reactions of 4 have been investigated. 7a However, compounds 4 -besides being Michael acceptors -can be considered also as ketene N,S-acetals of a _ special kind. The present enone synthesis is based on such chemistry.8 Allylic anions are derived from 4 quite readily by Y-deprotonation [Z-BuOK (1 equiv), DME, --3O"C, N21. Alkylation of these anions proved highly regiospecific, favouring a-alkyl derivatives 5 to the exclusion of any significant amounts of the Y-isomer [R3X (1 equiv), 1 h, -30" to 2O"Cl. By this reaction the C,C double bond shifts position. The highest yields of 5 -2585