ORGN 313 |
| The Pauson-Khand reaction, a formal transition metal mediated [2+2+1] cycloaddition of an alkyne, an alkene and carbon monoxide, is nowadays one of the most convergent and practical methods for cyclopentenone synthesis. Recently, our research group have demonstrated that Mo(CO)3(DMF)3 promotes Pauson-Khand reactions under very mild conditions (rt or 0oC) in the absence of any promoter. The heteroatom variant of the reaction, in which the alkene is substituted by a carbonyl group to afford α,β-unsaturated γ-butyrolactones, has been much less studied. In this context, we envisaged that the use of more reactive molybdenum species could promote hetero-Pauson-Khand reactions without needed of carbon monoxide atmosphere. The reactions of yne-aldehydes with Mo(CO)3(DMF)3 take place under very mild conditions (THF, rt) in the absence of any additive. The scope of the process is rather broad, tolerating the presence of a wide variety of substituents and functional groups at the 1,6- and 1,7-enyne framework.
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Metal-Mediated Reactions and Syntheses
1:00 PM-5:00 PM, Monday, 11 September 2006 Moscone Center -- Room 133, Oral
Division of Organic Chemistry |
