Cyclobutane, propyl

From the observed drop in yield, one can calculate the rate of Reaction 10 relative to hydride transfer with cyclobutane (on the rate scale used in Table I) as 1.55 for the ethyl ion and 0.83 for the propyl ion. 

A low ion pair yield of products resulting from hydride transfer reactions is also noted when the additive molecules are unsaturated. Table I indicates, however, that hydride transfer reactions between alkyl ions and olefins do occur to some extent. The reduced yield can be accounted for by the occurrence of two additional reactions between alkyl ions and unsaturated hydrocarbon molecules—namely, proton transfer and condensation reactions, both of which will be discussed later. The total reaction rate of an ion with an olefin is much higher than reaction with a saturated molecule of comparable size. For example, the propyl ion reacts with cyclopentene and cyclohexene at rates which are, respectively, 3.05 and 3.07 times greater than the rate of hydride transfer with cyclobutane. This observation can probably be accounted for by a higher collision cross-section and /or a transmission coefficient for reaction which is close to unity. 

Proton transfer from H3 + and CH5+ to cyclopropane yields a C3H7 + ion, which at atmospheric pressures is largely stabilized by collision (9). This ion reacts as a sec-propyl ion with an added interceptor molecule (9). Hence, the protonated cyclopropane ion undergoes ring opening to acquire the sec-propyl ion structure. Similarly, it has been shown that protonated cyclobutane rearranges to the sec-C4H9 + structure. 

It may be suspected that the genuinely topotactic (as secured by the molecular precision of the AFM [18]) photodimerization of 2-benzyl-5-benzyli-denecyclopentanone [118] might be a good candidate for a quantitative preparative photo dimerization to give the head-to-tail anti-[2+2] dimer. Early quantitative solid-state [2-1-2] photodimerizations (most of the published mechanistic interpretations of which can no longer be accepted) are listed in [110]. These deal with the anti dimerization of acenaphthylene-1,2-dicarboxylic anhydride, the head-to-head syn dimerization of acenaphthylene-1-carboxylic acid, the syn dimerization of 5,6-dichloroacenaphthylene, and the thermally reversible head-to-tail anti dimerization of seven ( )-2,6-di-f-butyl-4-(2-aryl-ethenyl)pyrylium-trifluoromethanesulfonates. All of these reactions proceed fully specific. On the other hand, quantitative photoconversions of a 1 1 mixed crystal of ethyl and propyl a-cyano-4-[2-(4-pyridyl)ethenyl]cinnamates gives mixtures of diesters with one (A>410 nm) or two cyclobutane rings (no cutoff filter). 

Similarly, (ft)-( + )-6,6-dimcthylbicyclo[3.1, l]heptan-2-one [(R)-( + )-nopinone, 59] undergoes boron trifluoride promoted cyclobutane cleavage to give in 68% yield (4/ )-l-acetoxy-4-(2-acetoxy-2-propyl)cyclohex-l-ene (60).168,169... 

Bicyclo[2.2.1]hept-2-en 5-Nitro-5-propyl- V/lc, 1071 (Diels-Alder) X/l, 397f. (Diels-Alder) Cyclobutan 1 -Cyan-3,3-dimethyl-l-ethoxycarbonyl- E17e. 226 [TosO —C2 —en(CN)2 + BH Ethanol]... 

Cyclobutan 2-Ethoxy-1-(1-hydroxy-propyl)- -methyl- E17e. 359 (6-OR —subst. 5,6-H2 —4H-pyran + H5C6-MgX) Cyclodecan trans- 1,2-Dihydroxy-Vl/la, 1, 611 Cyclohexan... 

A series of diamides of cyclobutane-1,1-dicarboxylic acid gre prepared and reported to have depressant properties. The activity of bis 1,1,l-trichloro-2-propyl)-1,2-cyclobutane-dicarboxylate was shown to be due to the in vivo hydrolysis to the known hypnotic 1,1,l-trichloro-2-pro-panol. Preliminary pharmacological results in mice indi-... 

In n-hexane, direct C—C cleavage would lead to the formation of an n-butyl ion, so the detection of this product is not surprising. However, since the available evidence, discussed above, seems to indicate that the n-propyl ion does not retain its structure long enough to react, but rearranges within 10" sec to a more stable cyclic structure, we must examine the precursor of the CH3CH2CH2CH2D product for evidence that it, too, may have some alternate structure. Unfortunately, little can be said on this question. When ammonia is added to n-hexane, neither methyl cyclopropane nor cyclobutane are observed as products. " In fact, when cyclobutane is protonated... 

The isomer 42b rearranges to the compound 23, whereas 43a is thermally stable and does not exhibit dynamic properties. It is believed that the transformation of the cyclopropane derivative 43a to the cyclobutane derivative 45 occurs by the migration of the -propyl group with simultaneous ring enlargement (Scheme 2.30). Compound 45 in turn rearranges immediately to the more stable isomers 23a,b viaa [1,3]-B shift. 

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