Titanocene(II)‐Promoted Cross‐Coupling of Unsaturated Compounds.

Abstract

2006 C-C bond formation O 0282Titanocene (II)-Promoted Cross-Coupling of Unsaturated Compounds. -Conjugated dienes and allylic alcohols are prepared by the titanocene-promoted reaction of vinyl pivalate (I) with alkynes or carbonyl compounds. Unsymmetrical alkynes give single regioisomers. The formation of allene (V) supports an assumed reaction pathway leading via compounds of this type. Similar products are formed with complete stereospecificity if the reactions are performed with (Z)-sulfone (X). The corresponding (E)-sulfone does not react. -(OGATA, A.; NEMOTO, M.; ARAI, K.; KOBAYASHI, K.; TSUBOUCHI, A.; TAKEDA*, T.; Eur.