Synthesis and structure of the chromiumcarbonyl complexed phenyl allene

The chromiumtricarbonyl complexed phenyl allene 4 can be readily synthesized by palladium catalyzed hydride reduction or dimethyl cuprate mediated reduction of suitable propargyl ester derivatives 3 and 5. This parent compound of chromiumcarbonyl complexed aryl allenes is fairly stable and is unambiguously characterized by an X-ray structure analysis. Thiolate adds to 4 to give a 3.5:1 distribution between the nonconjugated and the conjugated addition products 7 and 8 in good yield.