Synthesis of 23-deoxy-25-epi north unit of cephalostatin 1 via reductive and oxidative modifications of hecogenin acetate

•23-Deoxy-25-epi north unit of cephalostatin 1 was prepared from hecogenin acetate.•23-Deoxy-25-epi north 1 synthesis involves multiple reductions and oxidations.•Key steps include stereoselective 5/5-spiroketalization.

An efficient synthesis of the 23-deoxy-25-epi north unit of cephalostatin 1 has been achieved in 17 steps via reductive and oxidative functionalizations of hecogenin acetate with an overall yield of 3.8%. This synthesis features transetherification-mediated E-ring opening, D-ring oxidation, hemiketalization-mediated E-ring closure, and stereoselective 5/5-spiroketalization.

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