1α,4α,4aβ,10aβ,5α,8α,8aβ,9aβ-octahydro-1,4:5,8-dimethanoanthracene-9,10-dione 、
dimethyl (1R,8S,9S,10S,12R,13R)-11,14-dioxapentacyclo[6.5.1.02,7.09,13.010,12]tetradeca-2,4,6-triene-10,12-dicarboxylate 以48%的产率得到tetramethyl (1R,2S,4R,5S,6R,7R,8R,9R,16S,17S,18S,19S,20R,21S,23R,24S,25R,26R,27R,28R,35S,36S,37S,38S)-3,22-dioxo-40,41,43,44-tetraoxapentadecacyclo[22.14.1.15,20.17,18.19,16.126,37.128,35.02,23.04,21.06,19.08,17.010,15.025,38.027,36.029,34]tetratetraconta-10,12,14,29,31,33-hexaene-7,18,26,37-tetracarboxylate