甲基锂 、
methyl <2S-<2α(S*),6β>>-6-<(benzoyloxy)methyl>-5,6-dihydro-α-methyl-5-oxo-2H-pyran-2-acetate 在
copper(I) bromide dimethylsulfide complex 作用下,
生成 methyl <2S-<2α(S*),3α,6β>>-6-<(benzoyloxy)methyl>-α,3-dimethyl-5-oxotetrahydro-2H-pyran-2-acetate 、 methyl <2S-<2α(S*),3β,6β>>-6-<(benzoyloxy)methyl>-α,3-dimethyl-5-oxotetrahydro-2H-pyran-2-acetate