Stereodefined tetraarylethylenes: Synthesis and applications

Luminescent materials with efficient aggregate‐state emissions are of growing interest due to their widespread applications in chemo‐/biosensing and optoelectronic devices. Aggregation‐induced emission (AIE) opens a new avenue for the applications of aggregate‐state luminescent materials. Among the AIE luminogens (AIEgens), tetraarylethylenes (TAEs) are typical AIEgens with a simple molecule scaffold and could be utilized as a framework for further elaboration, enabling structure‐property‐function relationship studies and multi‐functional applications. Since the existing approaches for the preparation of tetraarylethenes (TAEs) typically produce stereoisomeric mixtures, stereoselective synthesis of tetraarylethenes with desired geometry is a great challenge. In this review, we systematically compile the synthetic methodologies for the construction of TAEs in excellent regio‐ and stereoselectivities. The virtues and limitations of each methodology are discussed in detail as well. Meanwhile, the applications and the differences of properties between TAEs stereoisomers are introduced.