we report the development 
 of a catalytic method for the enantioselective 
 addition of indoles to pyrone - derived electrophiles . 
 arylpyrrolidino - derived 
 thioureas catalyze the addition with high stereoselectivity in the 
 presence of catalytic quantities of an achiral brnsted acid . 
 the indole 
 pyrone adducts feature a quaternary stereocenter 
 and represent an unusual class of indolines bearing structural resemblance 
 to the hybrid natural product pleiocarpamine .