Stereoselective Synthesis of the Revised Structure of -Lactone Polyketide from Diaporthe sp SXZ-19 and Its C-8 Epimer

Revised structure of -lactone polyketide from Diaporthe sp. SXZ-19 and its C8-epimer were synthesized from TBS protected (S)-lactaldehyde and 2,3-O-cyclohexylidene-d-glyceraldehyde, which was derived from d-mannitol. The target -lactones were prepared via a common alkyne intermediate utilizing alkyne-aldehyde coupling reactions by changing the reaction conditions. In addition, Carreira and Ohira-Bestmann reactions were used as key steps to achieve the targets.