α-Oxo-γ-butyrolactam, N-containing pronucleophile in organocatalytic one-pot assembly of butyrolactam-fused indoloquinolizidines.

The ambident reactivity of α-oxo-γ-butyrolactam has been explored in an organocatalytic one-pot Michael/Pictet-Spengler sequence. The synthetically interesting and medicinally important pentacyclic butyrolactam-fused indoloquinolizidines can be efficiently constructed in a highly stereocontrolled manner. Importantly, the chemistry described herein provides a general catalytic method for the enantioselective synthesis of butyrolactam-incorporated chemical entities.