S-2-methyl-3-(2-propynyl)-4-oxo-cyclopent-2-enol

(4S)-4-hydroxy-3-methyl-2-propargyl-cyclopent-2-en-1-one

(4S)-Hydroxy-3-methyl-2-(2-propynyl)-2-cyclopentene-1-one

(4S)-4-hydroxy-3-methyl-2-prop-2-ynyl-cyclopent-2-en-1-one