We report the total syntheses of two indole diterpenoid natural products, paspaline A and emindole PB. Paspaline A is synthesized in a 9-step sequence from commercially available materials. The first total synthesis of emindole PB is accomplished in 13 steps and confirms a previously ambiguous structural assignment. Density functional theory calculations are utilized to interrogate the key carbocationic rearrangement in a predictive capacity to aid in the selection of the most favorable precursor substrate. This work highlights how retro-synthetic design can be augmented with quantum chemical calculations to reveal energetically feasible synthetic disconnections, minimizing time-consuming and expensive empirical evaluation.