Chemoenzymatic routes to cyclopentenols: the role of protecting groups on stereo- and enantioselectivity

Enantiopure (R)-4-triisopropylsilyloxycyclopent-2-en-1-one was obtained through short sequences including either the enzymatic resolution of racemic cis-4-triisopropylsilyloxycyclopent-2-en-1-ol or the enzymatic desymmetrization of cis-cyclopent-2-en-1,3-diol. Alternatively, the enantiopure (S)-4-triisopropylsilyloxycyclopent-2-en-1-one was very efficiently obtained from diacetate of cis-cyclopent-2-en-1,3-diol using enzymatic desymmetrization with CAL-B. In these sequences, TIPS proved to be the best protecting group.