been achieved by condensation of methylmalonyl dichloride with ethyl trans-4-methyl-3-oxo-4-hexenoate followed by hydrolysis, decarboxylation, and methylation of the resulting 3-methyl-4-hydroxy-5-carbethoxy-6-(trans-1-methyl-1-propenyl)-2-pyrone. Exploration of an alternate scheme involving the dehydrogenation of 6-substituted-4-methoxy-5,6-dihydro-2-pyrones, prepared by Reformatsky reaction of ethyl
Nazarov cyclisation of dienone-esters and tetrahydropyrones using trimethylsilyltriflate
作者:John F.P. Andrews、Andrew C. Regan
DOI:10.1016/0040-4039(91)80577-s
日期:1991.12
Cyclopentenone esters have been synthesized via a Nazarov cyclisation of the corresponding alpha,alpha'-dienone esters or tetrahydro-gamma-pyrone esters employing trimethylsilyltriflate at room temperature. The dienone esters were synthesised by a short two-step acylation-Knoevenagel sequence.