Explorations on the Asymmetric Total Synthesis of Isoschizogamine

Two approaches to the synthesis of isoschizogamine were reported. Both routes utilized an efficient
aza-Claisen rearrangement to establish the absolute stereochemistry of the all-carbon quaternary center
in the natural product. In the first approach, a highly diastereoselective (10:1) hetero-Diels−Alder reaction
was utilized to reach a densely functionalized tetrahydroquinoline derivative as an advanced intermediate
to the targeted alkaloid. An acylamidine intermediate was prepared and studied in the intramolecular
cyclization reaction under acidic conditions in our second approach.