Trityl bromide was obtained from Aldrich and 6-iodo-l-heptene(1) was prepared from its tosylate and sodium iodide as reported earlier.6 5-Chloro-l-cyclooctene (4), 5-bromo-l-cyclooctene (3), and 5-iodo-l-cyclooctene (2) can be obtained in nearly quantitative yield by Pritzkow's method of adding dry HX to 1,5-cyclooctadiene in CH2C12.13Gas chromatographic analyses were conducted on a Hewlett-Packard Model 700 instrument using a FID detector and packed columns. Quantitative GLC analyses were obtained with the use of response factor corrected peak areas using internal standards.Infrared spectra were recorded on a Perkin-Elmer Model 621 spectrophotometer.Mass spectra were obtained on a Varían MAT 112S, and for EPR studies spectra were recorded on a Varían E 109 ES.General Procedure for Reduction of Alkyl Halides. The appropriate amounts of alkyl halide (0.1 M) and metal hydride (0.2 M) were combined in a reaction tube under N2 in THF and shielded from light. For the EPR study, the reagents were combined in an EPR tube under N2. In those cases where DCPH or DCPD were employed, the additive was added to the metal hydride, followed by the addition of the appropriate alkyl halide. Control experiments showed that no reaction occurred between LiEtgBD and DCPH, as determined by the constancy of the P-H (13) Franz, H.

When alkenes are oxidized by quaternary ammonium or phosphoniurn permanganates in polar organic solvents, such as acetone, the structures of the cations have little or no effect on the rates of reaction. In less polar solvents, such as methylene chloride or toluene, the rates of reaction are, however, dependent on' the identity of the quaternary ammonium or phosphonium ions. It thus appears as if the reacting species may exist as solvent-separated ion pairs in polar solvents and as intimate ion pairs in nonpolar solvents. The rates of reaction are also very sensitive to substituent effects, a nonlinear (concave upward) Hammett plot being obtained for the oxidation of substituted P-bromo and P-methoxystyrenes. The mechanism is best visualized as proceeding by way of a continuum of transition states that can vary from electron rich to electron poor depending on the capacity of the substrate structures to accommodate either negative or positive charges. Lorsque des alctnes sont oxydCs par des permanganates d'ammonium ou de phosphonium quaternaires, dans des solvants organiques polaires c o m e l'acttone, les structures des cations n'ont pas ou peu d'effet sur les vitesses des rkactions. Dans des solvants moins polaires, c o m e le chlomre de mkthylbne ou le tolubne, les vitesses dkpendent toutefois de I'identitC des ions quaternaires. I1 semble donc que les entitCs qui rCagissent peuvent exister sous la forme de paires d'ions solvatCsdans les solvants polaires et de paires d'ions intimes dans les solvants non-polaires. Les vitesses de rkaction sont aussi trbs sensibles aux effets de substituants: on obtient une courbe de Hammett qui n'est pas 1inCaire (concave vers le haut) lors de l'oxydation de P-bromo et de P-mCthoxystyri?nes substituks. La meilleure reprksentation du mkcanisme de la rCaction implique des Ctats de transition continus qui varient suivant leur nature riche ou pauvre en Clectrons, qui dCpend elle-mkme de la capacitk des structures des substrats d'accommoder soit des charges positives ou nCgatives.[Traduit par la revue]

. Can. J . Chem. 60, 2456 (1982). The abilities of various cyclic and acyclic polyethers to solubilize potassium permanganate in organic solvents have been compared. In general, the cyclic compounds (crown ethers) are more effective than acyclic polyethers of comparable molecular weights. Each mole of 18-crown-6 is capable of solubilizing one mole of potassium permanganate in most solvents whereas the corresponding linear polymer, dimethyloctaethylene glycol, is much less effective, particularly in solvents of low polarity. Very long chain polymers are capable of complexing more than one mole of potassium ion per mole of polyether and thus bringing more than one mole of potassium permanganate into solution. A comparison with other studies on acyclic polyethylene glycols suggests that these structures would be helical with the oxygen complexed potassium ions inside and the permanganate anions arranged along the exterior.

No abstract

This work is part of a study of the properties of a series of quartenary ammonium and phosphonium permanganates. The title compound v1as recrystallized from a methylenechloride-carbon tetrachloride mixture. Two crystalline forms v1ere found. The first (a) is orthorhombic, space group Pbc2,, a= l2.626(3)A 0 , b = l4.832(26)A 0 , c = l9.806(7)A 0 , Z = 8. The second form (S) is monoclinic, space group P2,jc. Assuming Z = 4 for the S form, the calculated densities are identical (1 .42 g cm-3). The intensity data for the (a) form were collected with a Picker four-circle automated diffractometer controlled by the NRCC Diffractometer Control System (D.F. Grant, E.J. Gabe, Am. Cryst. Assoc. Abstracts, 2, 245, (1974)). The space group was assumed to be Pbcm ( = 0.81). However, the Patterson map did not show the expected peaks of the form (DOw), associated with the mirror plane. A solution was then attempted in the non-centrosymmetric space group Pbc2, using the version of the direct methods program MULTAN, contained in the NRCC program system. The structure \vas refined by block-diagonal least squares with anisotropic temperature factors to a conventional R factor of 0.086, using the 2110 independent reflections with sin B/A 5 0.60 and I/o(I) > 2.0. The structure contains two formula units in the form of ion pairs related by a local non-crystallographic center of symmetry. Each of the permanganate ions is found near the methyl group of a cation, which allows the closest approach of the permanganate ion to the positive charge centre. The B form is currently under investigation. The most unusual feature of the complex, the tr.vo 4-membered Co-N-C-N rings r.vith a coTILrnon nitrogen atom, shor.vs that two ring closures both using only one carbon atom occurred in the condensation. As a result, the angles subtended at tne metal by the donor nitrogens Nl, N3 and N4 are just.72 & 73°1 and the bridging carbon atoms Cll, Cl2 are only 2.47A from the metal. 08.2-44 SYNTHESIS !I.ND CRYSTAL STRUCTURES OF CAGEDAn expected nnitromethyln cap closes off the opposite side of the complex, r.vhich has in total very approximate mirror symmetry.The novelty of this structure has prompted a corrobative investigation into less suitable crystals of the minor product formed in the same reactions. !l~alysis and structural details of both compounds and of the synthetic mechanisms will be presented. 08.2-45PHASE RELATIONS AND CRYSTAL STRUCTURES IN THE SYSTEM WATER -HYDROGEN FLUORIDE.