Diastereoselective Syntheses of Indoloquinolizidines by a Pictet−Spengler/Lactamization Cascade

An expedient diastereoselective synthesis of highly functionalized indolo[2,3-α]quinolizidines adopting a cis H2/H12b geometry has been realized by a Pictet-Spengler/lactamization cascade sequence. The absolute stereochemistry at C2, C3, and C12b was governed by the originally created chirality of the Michael adduct through organocatalyzed conjugate addition of dialkyl malonates to α,β-unsaturated aldehydes.