Allenes, stereodefined synthesis

Besides the acetylene—acetylene coupling reactions shown above, acetylene—allene [40] and allene—allene coupling reactions [40] are also feasible (Eqs. 9.18 and 9.19). These reactions provide convenient methods for the synthesis of stereodefined olefinic skeletons. As an addendum, the coupling of vinylsilane with acetylenes was effected by 1 to give stereodefined homoallylsilanes, as shown in Eq. 9.20 [41]. 

Yudha, S., Kuninobu, Y, Takai, K. (2008). Rhenium-catalyzed synthesis of stereodefined cyclopentenes from b-ketoesters and aliphatic allenes. Angewandte Chemie International Edition, 47, 9318-9321. 

---