Titanocene(II)-promoted stereoselective alkenylation utilizing (Z)-alkenyl sulfones

Article abstract of DOI:10.1021/jo070149u

(Chemical Equation Presented) The stereoselective alkenylation of unsaturated compounds by means of a (Z)-alkenyl sulfone-titanocene-(II) system is described. Treatment of alkynes and (Z)-alkenyl methyl sulfones with the titanocene(II) reagent Cp₂Ti[P(OEt)₃]₂ produced conjugated dienes. This alkenylation system is also applicable to polar C=O bonds; the simple mixing of carbonyl compounds, (Z)-alkenyl methyl sulfones, and the titanocene-(II) reagent formed allylic alcohols. The advantages of alkenylation are that it requires no prepreparation of the alkenylmetal reagent and that it proceeds with complete stereoselectivity.