A convergent, catalytic asymmetric formal [4 + 2] annulation for the synthesis of dihydroquinolones has been developed. Carboxylic acids can be employed as precursors to NHC enolates through an in situ activation strategy. Simultaneous generation of a reactive aza-o-quinone methide under the basic conditions employed for NHC generation leads to a dual activation approach.

Enantioselective Annulations for Dihydroquinolones by in situ Generation of Azolium Enolates. -Substituents are tolerated in positions 4, 5, and 6 of the aminobenzyl chlorides, but not in position 3. The reaction can be scaled up. -(LEE, A.; YOUNAI, A.; PRICE, C. K.; IZQUIERDO, J.; MISHRA, R. K.; SCHEIDT*, K. A.; J. Am. Chem. Soc. 136 (2014) 30, 10589-10592, http://dx.