Synthetic studies towards pseurotin A. Part 3. Synthesis of a related highly functionalized γ-lactone

Article abstract of DOI:10.1002/hlca.19950780518

A new general concept for the total synthesis of pseurotin A (1), a secondary metabolite of Pseudeurotium ovalis STOLK, which possesses a highly substituted 1-oxa-7-azaspiro[4.4]nonane skeleton, is presented. A key intermediate of the planned reaction sequence is the functionalized γ-lactone 8. The corresponding protected compound 52 was prepared using (S)-O,O-isopropylideneglyceraldehyde (13) and the bromoacetal 14 as starting material. γ-Lactone 52 was obtained in enantiomerically pure state in ten steps. It possesses the desired configuration.