Enantioselective aza-Friedel-Crafts reaction of furan with α-ketimino esters induced by a conjugated double hydrogen bond network of chiral bis(phosphoric acid) catalystsElectronic supplementary information (ESI) available: Experimental procedure, characterization data, additional control experiments, copies of 1H NMR and 13C NMR spectra of all new compounds. CCDC 1520624, 1520625, 1834631 and 1834632. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c8sc02290

Chiral C 2 - and C 1 -symmetric BINOL-derived bis(phosphoric acid) catalysts, which have OP(&z.dbd;O)(OH) 2 /OP(&z.dbd;O)(OH)(OR) moieties at the 2,2′-positions, were developed and used for the enantioselective aza-Friedel-Crafts reaction of 2-methoxyfuran with α-ketimino esters for the first time. The intramolecular conjugated double hydrogen bond network is a key to increasing the Brønsted acidity and preventing deactivation of the catalysts. Highly functionalized α-amino acid derivatives with a chiral quaternary carbon center could be transformed into versatile optically active N - and O -heterocycles and an α-aryl-substituted serine. Chiral C 2 - and C 1 -symmetric BINOL-derived bis(phosphoric acid) catalysts facilitated the enantioselective aza-Friedel-Crafts reaction of 2-methoxyfuran with α-ketimino esters.