Efficient methods for deoxygenation of secondary and tertiary alcohols of some C19- diterpenoid alkaloids are presented. Delphisine (12) was converted to 1-deoxydelphisine (19) via either 1, 2-pyrodelphisine (17) or phenyl thionocarbonate 20. The following alkaloids were deoxygenated via their thiocarbonylimidazolyl derivatives: 14- acetyldelcosine (13) to 14-acetyl-l-deoxydelcosine (22); alkaline hydrolysis of 22 gave 1- ...
