lithium dimethylcuprate 、
methyl 2-ethyl-4-oxo-4H-1-benzopyran-3-carboxylate 以
四氢呋喃 为溶剂,
生成 、 rel-(2S,3S)-methyl 2-ethyl-2,3-dihydro-2-methyl-4-oxo-2H-1-benzopyran-3-carboxylate 、 rel-(2R,3S)-methyl 2-ethyl-2,3-dihydro-2-methyl-4-oxo-2H-1-benzopyran-3-carboxylate