Fig. 2: Substrate scope^a.

^aReaction conditions as stated in Table 2, entry 13, yields were isolated yields after purification by column chromatography, er values were determined via HPLC on chiral stationary phase. ^bThe reaction was carried out at 1 gram-scale based on 1a (6.4 mmol), 0.0005 mmol pre-NHC A, reaction time was 18 hrs.