B. Lal et al., FLUORINATION OF FORSKOLIN AND 1,9-DIDEOXYFORSKOLIN, Indian journal of chemistry. Sect. B: organic chemistry, including medical chemistry, 36(1), 1997, pp. 1-4
13-Formyl-1,9-protected-forskolin 3 is reacted with bromodifluorotriph
enylyhosphonium bromide 4 to give 15,15-difluoro-1,9-protected-forskol
in 5 which on deprotection affords the 15,15-difluoroforskolin 7. Iodo
fluorination at 14,15-double bond of 1,9-dideoxyforskolin 8 followed b
y base promoted dehydroiodination gives the required 14-fluorodideoxyf
orskolin 10 and the corresponding 7-acetyl migrated product 11.