A convenient asymmetric synthesis of the octalactin lactone

A facile asymmetric synthesis of the octalactin lactone was developed staring from (R)-cyclohexylideneglyceraldehyde (1). The key step of the synthesis is an In-mediated diastereoselective crotylation of 1 in water, which furnished the building blocks with the required stereochemistry under operationally simple conditions. Their conversion to the appropriate intermediates, invertive esterification and a ring closing metathesis reaction furnished the target compound.