Efficient synthesis of asymmetric epoxidation catalyst I

摘要

A process for the preparation of chiral ketone I from diol II comprising the acetylation of diol II with an acetylating agent, preferably an acetic acid derivative, wherein said acetylation is performed in the presence of a Lewis acid. The process can further comprise additional previous steps, so that chiral ketone I can be prepared in four steps starting from D-fructose. Alternatively, a process for the preparation of chiral ketone V from diol VI comprising the acetylation of diol VI with an acetylating agent, preferably an acetic acid derivative, wherein said acetylation is performed in the presence of a Lewis acid. The process can further comprise additional previous steps, so that chiral ketone V can be prepared starting from L-fructose, L-sorbose or D-arabinose.