Trioxypentafulvenes, 2 synthesis of 1‐substituted 2,3,6‐trioxypentafulvenes

Syntheses of 2,3,6‐trioxypentafulvenes with a free position at the ring are described, in which the protection of the C‐3 hydroxy group as methoxy or acetoxy derivative has been required. The difference in the behavior of the title compounds in relation to the previously reported 1,4‐disubstituted 2,3,6‐trihydroxypentafulvenes 2a‐e, which only exhibit enol forms, is discussed and attributed to the disappearance of the push‐pull system formed by the C‐3 enol group and the C‐4 electron‐withdrawing substituent.