Enol Acetates

Introduction

Enol acetates have enjoyed unique importance as intermediates in organic synthesis with a wide range of applications. [¹] The enol acetates are mainly employed in the transesterification of alcohols to synthesise chiral alcohols and acetates in high enantiomeric excess catalyzed by biocatalysts, such as lipases, [²] as well as the catalysts, such as iodine, [³] Cp₂Sm(thf)₂, [4] diethylzinc, [5] etc. They also find applications in the synthesis of biologically active intermediates like 1-acetyladamantane, [6] used as the starting material in the efficient preparation of the anti-influenza drug rimanadine and natural products, such as sapon­aceolides, [7] briarellin J, [8] etc.

Enol acetates are commercially accessible. Acetates of cyclic ketones can be easily prepared using perchloric acid and acetic anhydride. [9] Isopropenyl acetate is prepared on commercial scale by a sulfuric acid catalyzed reaction of acetone and ketene. [¹0] Whereas, the vinyl ester can be obtained by the reaction of ethylene and acetic acid with oxygen in the presence of palladium catalyst. [¹¹] Besides, chiral enol acetates have also been synthesized from racemic enol acetates or ketones through multistep reactions catalyzed by lipase and a ruthenium complex. [¹²]

References

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