The total synthesis of (+)-ryanodol. Part I. General strategy and search for a convenient diene for the construction of a key tricyclic intermediate

Abstract

This paper reports a retrosynthetic analysis that led to the conception of a synthetic strategy for the construction of ryanodol (2). The preparation of a key diene, i.e., spirolactone dienone 47 (19 → 31 → 33 → 48 → 49 → 52 → 47), and its Diels–Alder reaction with methyl vinyl ketone are reported. Keywords: strategy, synthesis, ryanodol, diterpene.