DIRECT FORMYLATION OF 9,9′-SPIROBIFLUORENE: 2-CARBOXALDEHYDE-9,9′-SPIROBIFLUORENE AND 2,2′-DICARBOXALDEHYDE-9,9′-SPIROBIFLUORENE

DIRECT FORMYLATION OF 9,9′-SPIROBIFLUORENE: 2-CARBOXALDEHYDE-9,9′-SPIROBIFLUORENE AND 2,2′-DICARBOXALDEHYDE-9,9′-SPIROBIFLUORENE