1-Octenyl bromide

The addition of a large excess of bis(cj-alkenyl)zinc compounds to the TiC -catalyzed polymerization of propene resulted in an increased polymer yield, but a reduction in the molecular weights of the polymers.64 This suggests that the diorganozinc compounds are both co-catalysts and chain-transfer agents in this polymerization. The catalyst activity decreased in the order bis(3-butenyl)zinc < bis(7-octenyl)zinc < chlorodiethylaluminum. Bis(7-octenyl)zinc was co-polymerized with propene to afford hexylzinc side chains, whose zinc-carbon moieties were converted to vinyl groups by the addition of allyl bromide. 

To a solution of 0.20 g of (-)-3a,5a-dihydroxy-2p-(3-oxo-trans-l-octenyl) cyclopentane-la-acetic acid y-lactone 3-benzoate in 15 ml of tetrahydrofuran at -78°C under nitrogen was added dropwise 3 ml etheral solution 3 M methylmagnesium bromide. The solution became heterogeneous after 2 hours, to the mixture was added 10 ml of saturated aqueous ammonium chloride and then ether and water. Organic extract was washed with brine, dried over sodium sulfate, and evaporated to give 0.21 g of (-)-3a,5a-dihydroxy-2p-[(3RS)-3-hydroxy-3-methyl-trans-octenyl] cyclopentane-la-acetic acid y-lactone 3-benzoate as a colorless oil [a]D = -80° (c 1.0, CHCI3). 

Retention of the stereo- and regiochemical identity of y monosubstituted allylic electrophiles is generally more difficult than that of -y,y-disubstituted analogs. Nonetheless, the Pd-catalyzed reaction of lithium cyclopentenolate in the presence of 2 equiv of BEts with ( )- or (Z)-2-octenyl acetate (but not chloride or bromide) proceeds satisfactorily, producing only minor amounts of undesirable by-prodncts (Table 2). High stereospecificity figures are, in fact, observable in the uncatalyzed reaction of lithium cyclopentenolate with (Z)-2-octenyl iodide and bromide, but the product yields were substantially lower. So, those results that are satisfactory in an overall sense are obtainable only in cases where the reaction is run with 2-octenyl acetate in the presence of BEts and a Pd catalyst. 

Dimethyl-2,6-octadienyl)triphenylphosphonium bromide stirred and refluxed 20 hrs. in water (7-hydroxy-3,7-dimethyl-2-octenyl)triphenylphospho-nium bromide. Y 90%. J. D. Surmatis and A. Ofner, J. Org. Ghem. 28, 2735 (1963). 

---