(<i>Z</i>)- and (<i>E</i>)-4,4-Dimethyl-5-oxo-2-pentenoic Acids and Their Derivatives
作者:Kunio Ito、Shingo Miyajima
DOI:10.1246/bcsj.59.815
日期:1986.3
(Z)-4,4-Dimethyl-5-oxo-2-pentenoic acid (1) exists almost exclusively in the hydroxy lactone form, the tautomeric equilibrium constant (K=[Ring]/[Chain]) being 2.8×103 in water as estimated by the pKa method. Several examples are described of preference for ring forms of derivatives of 1, which are capable of exhibiting ring-chain tautomerism. (E)-4,4-Dimethyl-5-oxo-2-pentenoic acid (7) reacts with