Bridged with 1,5-cyclooctadiene

Perhydro-diazocines 28, for the preparation of l,4-diamino-2,3-diol units that are the central structural elements in numerous biomaterials, were obtained from 1,3-cyclooctadiene, by reaction with diethyl azodicarboxylate (DEAD) to give the bridged 1,2-diazocine 103, which by ozonolysis gave the dialdehyde 104 that underwent... 

The bridging chloride ligands in these [Ir(olefin)2Cl]2 compounds are susceptible to metathesis reactions, yielding new dimeric compounds of the form [Ir(olefin)2B]2 where B represents a new bridging ligand. AUcoxides, thiolates, and carboxylates have all been employed successfully in the replacement of chloride. The complexes with B = Br, I have also been prepared, both by metathesis reactions and by direct reaction of cyclooctene or cyclooctadiene with IrBrs or Iris The olefin complexes also provide excellent starting materials for the syntheses of arene and cyclopentadienyl iridium complexes, a subject that will be discussed in the next section. 

With 1,5-hexadiene, the compound K2[(CaHio)Pt2Cle] with a bridging diene molecule can be obtained (283) this diene will form the complex (CeHio)PtCl2 as well in which it is chelated, probably with a gauche configuration (283) and which is less stable than the analogous complex with chelated 1,5-cyclooctadiene (284). 

Platinum complexes incorporating an optically active amine have been employed for resolution of racemic mixtures of optically active olefins by reaction of the olefin with dichloro-platinum(II). The differing solubility of the diastereoisomers permits separation by fractional crystallization and the olefin can be recovered by reaction of the complex with aqueous alkali cyanide. Using either (-f)-l-phenyl-2-aminopropane (Dexedrine) or (-f)- or (—)-a-phenyl-ethylamine. Cope and co-workers have resolved the optical isomers of trans double bond coordinated and, with (—)-phenylethyl-amine)dichloroplatinum(II), a bridged complex with each double bond coordinated to a different platinum atom. 

Reduction of [Ir(l,5-cyclooctadiene)Cl]2 with MgBrCi-CaHv) in diethyl ether, followed by photolysis with a mercury lamp, gives 12% yield of H4lr4(l,5-cyclooc-tadiene)4(C3H4), containing a bridging HC2CH3 unit. ... 

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