Primary activation of -quinone methides by chiral phosphoric acid for enantioselective construction of tetraarylmethanes.

Demonstrated here is an asymmetric nucleophilic addition primary activation of -quinone methides (-QMs) based on a chiral phosphoric acid catalytic system. In sharp contrast to previous CPA-based bifunctional activation processes that all required the nucleophiles to have an effective hydrogen bond donor unit (, OH, NH), here no such unit is required in the nucleophile. -protected indole nucleophiles were successfully utilized for the synthesis of chiral tetraarylmethanes with high efficiency and enantioselectivity under mild conditions.

Organocatalytic asymmetric synthesis of α-amino esters from sulfoxonium ylides.

Described here is the first organocatalytic asymmetric N-H insertion reaction of α-carbonyl sulfoxonium ylides. Without a metal catalyst, this reaction represents an attractive complement to the well-established carbene insertion reactions. As a stable surrogate of diazocarbonyl compounds, sulfoxonium ylides reacted with a range of aryl amines to provide efficient access to α-aryl glycines with excellent enantiocontrol in the presence of a suitable chiral phosphoric acid catalyst.