A multienzymatic pathway enables the preparation of optically
pure
spirolactone building blocks. In a streamlined one-pot reaction cascade,
the combination of chloroperoxidase, an oxidase, and an alcohol dehydrogenase
renders an efficient reaction cascade for the conversion of hydroxy-functionalized
furans to the spirocyclic products. The fully biocatalytic method
is successfully employed in the total synthesis of the bioactive natural
product (+)-crassalactone D, and as the key module in a chemoenzymatic
route yielding lanceolactone A.