Catalytic Enantioselective Biltz Synthesis

Abstract

AbstractThe Biltz synthesis establishes straightforward access to 5,5‐disubstituted (thio)hydantoins by combining a 1,2‐diketone and a (thio)urea. Its appealing features include inherent atom and step economy together with the potential to generate structurally diverse products. However, control of the stereochemistry of this reaction has proven to be a daunting challenge. Herein, we describe the first example of enantioselective catalytic Biltz synthesis which affords more than 40 thiohydantoins with high stereo‐ and regio‐control, irrespective of the symmetry of thiourea structure. A one pot synthesis of corresponding hydantoins is also documented. Remarkably, experimental studies and DFT calculations establish the reaction pathway and origin of stereoselectivity.