Tetranortriterpenoids. Part XV. Base-induced fragmentation of some swietenine derivatives
Abstract
The swietenine derivatives (3), (9), and (22) are transformed under basic conditions, with rearrangement, into the acids (4), (10), and (23), respectively whose structures are supported spectroscopically and by mechanistically reasonable modes of formation. The rearrangements are initiated by β-dicarbonyl fission at C(2)–C(3)[or C(1)–C(2)] of the bicyclononane system of swietenine. Attention is drawn to the structural diversity and unpredictability of the products.