99165-19-2Relevant academic research and scientific papers
Investigation of the Formation of Methyl 2-Cyano-2--4-oxopentanoate from Methyl 2,4-Dioxopentanoate. A Clarification of the Pathway for the Reaction of Trimethylsilyl Cyanide with Enolized β-Diketones
Foley, Louise H.
, p. 5204 - 5209 (1985)
The possible reaction pathways for the reaction of methyl 2,4-dioxopentanoate (1) with trimethylsilyl cyanide, with and without catalysts present, have been investigated by monitoring these reactions by 1H NMR.While all reactions of 1 with Me3SiCN, whether catalyzed or uncatalyzed, involve the initial formation of the silyl enol ether 5, it is not an intermediate in the formation of the cyanohydrin 3 from the reaction of 1 with Me3SiCN alone or in the presence of -CN.Evidence is presented which indicates that the silyl enol ether 5 and HCN are in equilibrium with 1 and Me3SiCN and that is the keto tautomer 1a, containing a very reactive α-keto ester group, which reacts with Me3SiCN to produce 3 (Scheme III).The existence of the equilibrium 5 + HCN 1 + Me3SiCN is demonstrated by isolation of the cyclic silyl enol ether cyanohydrin 9 when the silyl enol ether 5 is allowed to react with Me2Si(CN)2.Evidence that trialkylsilyl cyanides react with the keto tautomer of 1, and the exclusion of other possible reaction pathways, is obtained on reaction of 1 with t-BuMe2SiCN to give the tert-butyldimethylsilyl enol ether 10 and the unprotected cyanohydrin 11.The reaction of 2,4-pentanedione (4) with Me3SiCN, with and without the presence of catalysts, was reinvestigated and the mechanism is shown, in contrast with the earlier proposals, to be consistent with the mechanistic ideas presented here for the reaction of 1 with Me3SiCN.
REACTIONS OF TRIMETHYLSILYL CYANIDE WITH α-KETO ESTERS: SELECTIVE PREPARATION OF EITHER METHYL 4-(TRIMETHYLSILYL)OXY-4-CYANO-2-OXOPENTANOATE OR METHYL 2-(TRIMETHYLSILYL)OXY-2-CYANO-4-OXOPENTANOATE
Foley, Louise H.
, p. 1291 - 1298 (2007/10/02)
The reaction of methyl 2,4-dioxopentanoate (3) with TMSCN in the presence of zinc iodide affords the TMS protected cyanohydrin enol ether 4, from which the TMS protected cyanohydrin 1 can be obtained.Treatment of 3 with TMSCN alone gives the isomeric cyanohydrin 2.Reactions of two other α-keto esters with TMSCN are shown to proceed without a catalyst.
