Synthesis of the Western Half of the Lolicines and Lolitrems

The synthesis of the highly substituted indole portion of the complex tremorgenic natural products lolicine A and B is presented. The Diels−Alder reaction of a quinone monoimine enables the synthesis of an appropriately substituted indole. The key step in the synthesis is a tandem
isopropenyl cuprate addition/aldol cyclocondensation which provides the necessary functionality for elaboration to the 2,2,5,5-tetramethyltetrahydrofuran.