The recent advances in the contribution of chiral triarylmethanes and tetraarylmethanes with organocatalysts

Chiral triarylmethane skeleton is an important structural unit of many known compounds that are widely applied in organic functional materials and pharmaceuticals. Thus, the efficient construction of this class of compounds has attracted intensive attention from chemists. There are two main difficulties in synthesizing this type of compound: (i) the steric resistance of molecular structures would make it hard to be constructed; (ii) there are three similar aryl groups on the stereocenter, which is difficult to achieve stereo-identification. At present, the most common strategy is to introduce the third aryl group into a diarylmethane framework through the asymmetric Friedel-Crafts reaction or addition reaction of electron-rich arenes, so as to construct chiral triarylmethanes. In this review, we summarized the recent developments in the construction of various chiral triarylmethanes and chiral tetraarylmethanes from easily accessible compounds under organocatalytic conditions. This article describes based on the types of electrophilic reagents, mainly including quinone methides, indole imine methides, and azadienes. At the same time, we also emphasize the mechanism of each representative reaction, which might enlighten the future development of this field.