1-halo-substituted allenes, 11 - Yne-allenes from 1-bromoallenes and trimethylstannylacetylenes via palladium-mediated C-C coupling reactions

The Stille cross-coupling of the bromoallenes 3 with the stannylalkynes 6 o r distannylalkyne 8 provided a convenient route for the synthesis of the co njugated yne-allenes 7 or the diastereomeric yne-diallenes, meso-g and (R,R )/(S,S)-9. Analogously to 7, the phosphorylyne-allenes 14 were also prepare d under Stille conditions, starting from the phosphorylallenes 12 and propa rgylstannane 6a. Alternatively, yne-allenes 17 and 18 were obtained from he xadiynol 16 with orthoester 2b or diethoxychlorophosphane 13a by [3.3]- and [2.3]-sigmatropic rearrangements.