Addition of thallium triacetate to PFG2α methyl ester and related compounds in acetic acid. Nuclear magnetic resonance spectral study of novel dioxatricyclic and oxabicyclic products

Abstract

Addition of Tl(OAc)₃ in acetic acid to prostaglandin F_2α methyl ester (1) and its congeners (4) and (5) gave, with participation of 9-OH, the bicyclic enol ethers (26) which reacted in situ with a further equivalent of Tl(OAc)₃ to yield as the main products the dioxatricyclononane derivatives (2), (6), and (9) and (3), (7), and (10), respectively. Elucidation of the structure of the products by ¹H and ¹³C n.m.r. is presented and a mechanism of the transformations based on model studies is proposed.