The Decomposition of cis‐Fused Cyclopenteno‐1,2,4‐Trioxanes induced by Ferrous Salts and some oxophilic reagents

Two cis ‐fused cyclopenteno‐1,2,4‐trioxanes, 1a and 1b , were subjected to Zn in AcOH or FeCl 2 · 4H 2 O in MeCN. In the first case, the main course was deoxygenation to give cyclopentanone ( 18 ) and the 1,4‐diphenyl‐ or 1,4‐bis(4‐fluorophenyl)cyclopent‐3‐ene‐1,2‐diol 10 ( Scheme 5 ). In the second case, isomerization chiefly occurred resulting in the formation of a dimer 9 of the respective 3,5‐diaryl‐5‐hydroxycyclopent‐2‐enyl 5‐hydroxypentanoates 8 ( Scheme 3 ).