Palladium catalysed carbonylation of both 4-alkynyl-1,3-dioxolan-2-ones and alkynyl epoxides occurs under mild conditions to give methyl 5-hydroxy-2,3-dienoates which are converted to γ,δ-unsaturated δ-lactones by tandem conjugate additionâcyclisation with lithium dimethylcuprate or to methyl (E)-5-hydroxypent-3-enoates by stereoselective reduction with sodium borohydride.
钯催化的4-炔基-1,3-二氧烷-2-酮和炔基
环氧化物的羰基化反应在温和条件下进行,生成甲基5-羟基-2,3-二烯酸酯,这些产物可以通过与二甲基
铜锂的串联共轭加成-环化反应转化为γ,δ-不饱和δ-内酯,或通过与
硼氢
钠的立体选择性还原转化为甲基(E)-5-羟基戊-3-烯酸酯。