Conjugate addition of organocopper reagents to gamma-alkoxybutenolides and application to the synthesis of non-racemic alkyl cyclopentenones.
Simple organocopper reagents are shown to undergo anti-stereoselective 1,4-addition to menthyloxy-substituted lactone 1 in the presence of BF3.OEt2; the Lewis acid causes partial epimerisation of the acetal centre after conjugate addition. Enolate alkylation of the adducts leads to di- and trisubstituted lactones that are converted, in favourable cases, into di- and trisubstituted cyclopentenones.
Robertson
Jeremy
J
Department of Chemistry, University of Oxford, Chemistry Research Laboratory, Mansfield Road, Oxford, OX1 3TA.
Menard
Morgan
M
Ford
Rhonan
R
Bell
Stephen
S
D003300:Copper / Q000737:chemistry*; D006844:Hydrocarbons, Cyclic / Q000138:chemical synthesis*; D008956:Models, Chemical; D008958:Models, Molecular; D015394:Molecular Structure
D006844:Hydrocarbons, Cyclic; D003300:Copper