Synthesis of two novel C-19 analogues of (±)-alstoscholarisine A

Two new analogues of alstoscholarisine A, containing a phenyl or butyl substituent at the C-19 position, have been prepared in racemic form from the known skatole derivative. The syntheses of these compounds were accomplished in 13 steps, with a late-stage formation of the C-19 stereocenter. These derivatives are expected to have significantly changed biological activity, compared to alstoscholarisine A ? a potent neuroactive natural product.