Halogenation olefins

Aromatic, olefin, halogen aromatic, multihalogen paraffin without active H, monohalogen paraffin -1- -1- -1- 0 -1- 0 0 -1- 0 -1- 0 0... 

In the case of mono-olefins halogen substituents again reduce the basicity, as in the case of benzene. Unfortunately no information is available which would permit a comment as to whether the halogen atom causes this effect only if it is directly linked to the C=C double bond or whether an effect is also still exerted by an adjacent saturated halogen-substituted C-atom. With multiple halogen substitution the basicity falls even more as may be seen from the examples of chlorine-substituted ethylenes in Table 17. 

The multi-functionalized ketone A in Scheme 82 is reduced with an excellent ketone-selectivity with (R,R)-39 and a formic acid-(C2H5)3N mixture, affording (R)-B with 92% ee [321], The olefin, halogen atom, quinoline ring, and ester group are left intact. This product is a key intermediate in the synthesis of L-699,392 (LTD4 antagonist) [323],... 

Certain olefinic halogen compounds are best prepared by this method. Isobutylene bromide is dehydrohalogenated by hot potassium hydroxide... 

It WM nearly a century ago—in fact only a few years after Wurtz diacovered ethylene oxide that C ariva effected the earliest additions of hypohalous aeida to olefins, la the yoara that followed, many celohraicd obemiBis were among those who inveetigated thie reaction, which has been of great interest because of the paraUeluun betwem it and olefin halogenation. 

Thus, a large number of substances with the structural features shown above may form peroxides. However, these substances do not present a peroxide hazard to the same extent. The tendency of organic compounds to form peroxides decreases according to their structures as follows ethers and acetals > olefins > halogenated olefins > vinyl compounds > dienes > aUcynes > alkylbenzenes > isoparaffins > alkenyl esters > secondary alcohols > ketones > aldehydes > ureas and amides. 

The ion of this type was spectrally proved in the case of the reaction of adamantylideneadamantane with Bt2. The intermediate formation of the cation in olefin halogenation is also evidenced by the fact that halide ions accelerate this reaction. In acetic acid olefin bromination in the presence of Bf or Cf occurs with the rate... 

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