Acetonitrile bromo

G. TRIS(ACETONITRILE)BROMO(q4-l, 5-CYCLOOCTADIENE)-RUTHENIUM(II) HEXAFLUOROPHOSPHATE(l -)... 

BrF NjPRuC H, Ruthenium(II), tris-(acetonitrile)bromo(V-1,5-cyclo-octadiene)-... 

Molybdan (>/3-Allyl)-bis-[acetonitril]-bromo-dicarbonyl- E18, 78 [Mo(CO)6 + En + Nitril]... 

BrFjSCjHj, X -Sulfane, (2-bromoethenyl)-pentafluoro-, 27 330 BrF6N3PRuC 4Hj, Ruthenium(II), tris-(acetonitrile)bromo(Ti -l,5-cycloocta-diene)-, hexafluorophosphate(l -), 26 72... 

As an improved alternative to the direct cyclocarbonylation of allylic halides and acetylene derivatives, a two-step procedure has been reported49. Thus, the addition of allylic halides to acetylenic derivatives is catalyzed by palladium(II) complexes, such as bis(acetonitrile)bromo-palladium(ll), followed by cyclocarbonylalion of the resulting cfs-adducts of the alkyne with tetracarbonylnickel in acetonitrile containing precise amounts of methanol and triethylamine. This is a better procedure for the preparation of cyclopentenones than direct cyclocarbonyla-tion mediated by tetracarbonylnickel, especially for monosubstituted or weakly polarized, disubstituted acetylenes. 

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