Studies in Polypropionate Synthesis: Stereoselective Synthesis of (-)-Denticulatins A and B.

Article abstract of DOI:10.1016/S0040-4039(00)77719-7

(-)-Denticulatin B (2) was prepared in 9 steps (20percent yield) with 70percent overall ds starting from the ethyl ketone (R)-8.Key steps are the novel boron-mediated aldol/reduction, 8 -> 12, the titanium aldol coupling, 6 + 5 -> 18, and the HF-pyridine cyclisation, 20 -> 2.Epimerisation at C₁₀ in 20 led to (-)-denticulatin A (1).