di-t-butyl 3,8,12,17-tetra(2-methoxycarbonylethyl)-2,7,13,18-tetramethyl-a,c-biladiene-1,19-dicarboxylate dihydrobromide 在
溴 、
三氟乙酸 作用下,
生成 3,3',3'',3'''-(2,7,13,18-tetramethyl-1,19-dioxo-19,21,22,24-tetrahydro-1H-bilin-3,8,12,17-tetrayl)-tetra-propionic acid tetramethyl ester