Ryanoids and related compounds. Identification of five new ryanoids from the plant Ryania speciosa Vahl. Formal total syntheses of 3-deoxyryanodol (cinnzeylanol), 10-O-acetyl-3-deoxyryanodol (cinnzeylanine), 2-deoxyryanodol, 2-deoxy-2-epiryanodol, 2,3-dideoxy-2,3-dihydroryanodol, 2-deoxy-3-epiryanodol, and 2-deoxy-3-epiryanodine

In the course of a preliminary investigation on the relationships between the chemical structure of ryanoids and their affinity to the ryanodine binding site, we have isolated, from the plant Ryania speciosa Vahl, four new members of this family of natural insecticidal compounds (ryanoids 3, 4, 5, and 6) and corrected the reported structure of a fifth one (ryanoid 7). In addition, we have synthesized, from anhydroryanodol (10), new members of this family having fewer hydroxyl groups in ring A: cinnzeylanol (14) and cinnzeylanine (15), 2,3-dideoxy-2,3-dihydroryanodol (16), 2-deoxy-3-epiryanodol (18), and 2-deoxy-3-epiryanodine (19), 2-deoxyryanodol (20), and 2-deoxy-2-epiryanodol (21).