The same research group has recently applied this method to a formal synthesis
of γ-rubromycin 58 [188] (Scheme 91). Treatment of phenol 380 with hypoiodite in
the presence of TBAF as a fluoride ion source afforded the 5,6-bis(benzannulated)
Scheme 89 IHA-based syntheses of cryptoacetalide and danshenspiroketallactone [183, 184]
Scheme 90 Xue et al.’s hypoiodite approach toward bis(benzannulated) spiroacetals [187]
Synthesis of 5,6- and 6,6-Spirocyclic Compounds
251
of γ-rubromycin 58 [188] (Scheme 91). Treatment of phenol 380 with hypoiodite in
the presence of TBAF as a fluoride ion source afforded the 5,6-bis(benzannulated)
Scheme 89 IHA-based syntheses of cryptoacetalide and danshenspiroketallactone [183, 184]
Scheme 90 Xue et al.’s hypoiodite approach toward bis(benzannulated) spiroacetals [187]
Synthesis of 5,6- and 6,6-Spirocyclic Compounds
251