In all cases, the most important reaction observed was the isomerization of the epoxide to a carbonyl function. Formation of the latter ring system appears to be slightly favored over formation of the six-membered ring. In the cyclization of the cis,~-diene this control is partially lost due to highly unfavorable conformational effects.
INFRARED SPECTRA CF CYCLOBUTANE COMPCU!\TDS In an attempt to locate the possible characteristic frequencies of C. Ste;) first seen in Bloomfield's mechanism wa;;: fast and . reversible addition of a proton to a polyene double bond. A specific example of the more general scheme is given by the conversion of neral (lila) to racemic 4-isopropylidcnyl-cyclohexen-3-ol (llld} (41).
Consequently, tlri's theory undoubtedly accomplishes an oversimplification of the biogenetic mechanics of cyclization processes. Herein lies the potential utility of the Ruzicka theory; its beauty is due to its striking simplicity.
F OOT N OTE STO TABLE I
Taking into account the magnitude and dh·0ction of the error in the calculated entropies, however, the difference is 4. However, it is impossible to qualitatively determine the nature of this restricted motion based on the entropy data alone. Due to the presence of vinyl hydrogen at C-2 and C-4, the conformation IXa,b would be expected.
Olefins (i.e. reductions due to the priority of the new double bond are given as a positive value:::); (d) See footnote ::1 appropriate to the composition or its constants given in Table I; {e). Since the collision zone depends on the conformation of the molecule, the viscosity data for the hydrocarbon::~ of Table<:;. 4. pressures due to eclipsed groups, and at the same time w.::)Uld change the nature of the overlap in the system.
The width of the curve in Figure o iG due to the fact that ,>mall rotations, which do not result in large changes in the overlay-, value·3, give rise to relatively large separation between C -1 and C - 6. An important obset·vation here i;:; which ciue to the relative oTientations. information regarding:S the confor~·national. course of the reaction can be obtained from less common systems. differentiation bet·.vecn the t'.vo hypoteaizecl.
HOO~H
Only starting material was recovered when XXIV was treated with an acid exchange resin (Amberlite IR -120) for varying periods up to one week at room temperature. ). Such a rationale would also account for the fact that rnet..h.yl heptenone o:d cle (XXIV) does not cyclize under these conditions. benzene is believed to be the result of this solvent not being basic enough to remove. The 0'-hydrogen of the intermediate carbonium ion. i), which therefore seek out the oxygen electrons. By taking the spectrum of this material in p-dioxane, which effectively reduces the concentration of acid dimers in solution (93), it was possible to !:"Jake, with rea.:;onable certainty, the assignments shown in Table UI.
Treatment of crude 6,7-opoxy-1-hcptenc with -;tron:3 acid led to a mixture of aldehydes (po::~itive Tollen';; te3t). whose infrared spectrum was very similar to that of 5-hydroxy-1-hexal. Cyclization of Methyl Geranate: Methyl 3eranate was cyclized using the same procedure (L:A) used in the isomerization of geranic acid. temperature and the time the ester remained in contact with the acid did not affect the overall yield of the reaction, but did change the relative amounts of t!-cyclogeranic acid and methyl rv.-cyclogeranate isolated from the reaction. mixture. The darkened solution was then poured onto ice and. the aqueous mixture was continuously extracted with ether.
After this period the mixture was diluted to 5 ml. with water and neutralized with 2 N. The aqueous solution was thoroughly extracted with ether, which was rinsed with a small arnou'!'lt of a saturated solution of sodium sulfate. To this was added with stirring over a period of time. The mixture was stirred with a high speed stirrer for two days. chloroform solution was washed with an excess of 2 N sodium hydroxide solution followed by a satd. solution of Zerrous sulphate, and then with water. Based on the presence of 47o/o of the monoxide in the .. starting material, the yield was 33%.
Oo method, the meaning attached to these values can only be questionable. However, the ordering of the relative stabilities can be very instructive, in that it suggests which types of systems might be expected to favor the stability. formation of non-classical intermediate ions due to a gain in resonance: tabilization. In contrast, the bottom right corner of Table IV might be expected to show little tendency to do so. formation of non-classical ions. The treatment undoubtedly rests largely on the assumption that all non-classical systems would be symmetric; that is, that all k. The les3 symmetric;,;yatems would require that. electrons are placed in the more localized cr bond, which is formed on the outside of the olefin's original iT bond. result in a corresponding decrease in the delocalization energy. An even higher boiling liquid fraction could not be easily chronographed in the gas phase on the same column material without severe decomposition, and therefore it was not investigated...assuming it consists of C...the possibility of polychlorinated materials with fewer carbon atoms cannot be excluded.
Sites of saturation are assumed to arise from time to time. defect in the intramolecular sequence step. Entry into this area of understanding is hindered by the lack of kinetic data for these extremely fast reactions, and currently the techniques for obtaining this information are largely inadequate. Otherwise, the C-1 hydrogen would migrate to C-2 at the same time that the bond between C-1 and the t-butyl group v1 is fully developed.* Lack of symmetry in the arrangement of the oZ! group.
