Stereodivergent Ruthenium-Catalyzed Transfer Semihydrogenation of Diaryl Alkynes

Li and Hua have reported a stereodivergent triruthenium dodecacarbonyl [Ru₃(CO)₁₂] catalyzed transfer semihydrogenation of various diaryl alkynes with DMF/water as a hydrogen source to give (Z)- and (E)-stilbenes, selectively. The stereoselective syntheses of (Z)- and (E)-stilbenes were achieved by the use of acetic acid and trifluoroacetic acid as additives, respectively. The processes have been applied to the preparation of analogues of cis-combretastatin A-4 and trans-resveratrol.