Polyhydroxylated pyrrolizidine alkaloids from transannular iodoaminations: application to the asymmetric syntheses of (-)-hyacinthacine A1, (-)-7a-epi-hyacinthacine A1, (-)-hyacinthacine A2, and (-)-1-epi-alexine.

Polyhydroxylated pyrrolizidine alkaloids from transannular iodoaminations: application to the asymmetric syntheses of (-)-hyacinthacine A1, (-)-7a-epi-hyacinthacine A1, (-)-hyacinthacine A2, and (-)-1-epi-alexine.