Cyclohexene complexes

Cyclohexaselenium, 28 137-142 Cyclohexasulfur (S ), 18 288, 293, 294 Cyclohexene complexes with gold, 12 348 with silver, 12 342... 

The cyclohexadiene complex 29 has been further elaborated to afford either the cydo-hexenone 34 or the cyclohexene 36 in moderate yields (Scheme 1) [21]. The addition of HOTf to 29 generates the oxonium species 33, which can be hydrolyzed and treated with cerium(IV) ammonium nitrate (CAN) to release the cyclohexanone 34 in 43 % yield from 29. Alternatively, hydride reduction of 33 followed by treatment with acid eliminates methanol to generate the r 3-allyl complex 35. This species can be trapped by the conjugate base of dimethyl malonate to afford a cyclohexene complex. Oxidative decomplexation of this species using silver trifluoromethanesulfonate liberates the cyclohexene 36 in 57 % overall yield (based on 29). 

In HB(pz)3Cu(C2H4)CuCl, the HB(pz)3 moiety is bidentate, the third pyrazolyl group coordinating to CuCl A similar structure was found in the analogous cyclohexene complex . 

Oxidation of cyclohexene to the oxide. Decomposition of the chromyl chloride-cyclohexene complex, suspended in CH2C12, with cold 5 % aqueous sodium bicarbonate allowed isolation of cyclohexene oxide in 1.5% yield.3... 

NMR for the reaction of a hydrido( -cyclohexadienyl)cyclohexene complex of ruthenium(II) . Insertion of both activated and unactivated alkenes into the Ru—H bond of K[(PPh3)2Ph2PCgH4RuH2] CioHg (C2H5)20 also occurs, although isolable (T-alkylruthenium species are not yet characterized . 

Irradiation of cyclohexene in the presence of CuOTf produces the dimers 14 (49%) and 15 (8%), along with the cyclohexylcyclohexene 16 (24%) (Scheme 5)T The stereochemical outcome in Cu(I)-catalyzed dimerization of cyclohexene may be the result of cis-tram isomerization on irradiation of the initially formed Cu(I)-cyclohexene complex to the trans-cyclohexene-CuOTf complex 13, followed by a concerted ground state 2 + 2 cycloaddition of the highly strained tram-cyclohexene to another cyclohexene. Cycloheptene, on the other hand, produces the aU tra s-fused trimer 17 (Scheme 6) as the sole product. A 1 3 CuOTf-trans-cycloheptene complex has been proposed to be the precursor of this product. No dimerization reaction has been observed for cyclooctene and acychc olefins.However, mixed photocycloaddition occurs with cyclooctene if the other olefin is sufficiently reactive. Thus, cyclooctene adds to norbornene to produce the cyclobutane derivative 18 in 40% yield. GDdimerization was also observed when a mixture of cyclohexene and cycloheptene was irradiated in the presence of CuOTf to yield the adduct 19 (Scheme 6). ... 

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