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

An expedient diastereoselective synthesis of highly functionalized indolo[2,3-α]quinolizidines adopting a cisH2/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. [ABSTRACT FROM AUTHOR]