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 benzhydrylphosphonium salts in a regioselective manner, (2) followed by a chemoselective Wittig-type olefination with (deuterated) formaldehyde. This approach affords (deuterated) 1,1-diarylethylenes in good yields with high levels of isotopic incorporation. This protocol provides straightforward access to versatile building blocks of interest for synthetic and medicinal applications.