Investigations directed at the total synthesis of ouabain. Lessons learned from degradation studies

Article abstract of DOI:10.3987/com-99-s142

A procedure has been developed for transforming pentacyclic Heck product (8) to enone (10), an intermediate having appropriate functionality for future elaboration of the C1 and C3 diol functionality of ouabagenin. The plant-derived cardiac glycoside ouabain has been degraded to analogs (17) and (20) that contain, respectively, a Δ^9.11 double bond and C17 nitrile. These intermediates should be useful in future efforts to develop chemistry for functionalizing the Δ^9.11 double bond of 8 to incorporate C11 oxidation and for elaborating the β C17 nitrile of this advanced synthetic intermediate to a β butenolide.