The Designed Synthesis of Unsymmetrical (Deuterated) 1,1-Diarylethylenes via Simple Sequential Coupling of Arenes and Aldehydes

A practical and efficient method for synthesizing unsymmetrical (deuterated) 1,1-diarylethylenes is reported. The strategy relies on simple and selective sequential coupling processes in which (1) commercially available arenes react with aldehydes to form regioselective benzhydryl phosphonium salts, (2) followed by a chemoselective Wittig-type olefination with (deuter-ated) formaldehyde. This approach affords (deuterated) 1,1-diarylethylenes in good yields with high levels of isotopic in-corporation. This protocol provides straightforward access to versatile building blocks of interest for synthetic and medicinal applications.