Many chemists are acquainted with observations of fast reactions such as may occur during low-temperature storage of frozen solutions. Usually such "frozenstate reactions" are not of primary interest; in fact, they are often taken only as troublesome technical problems. Until recently, therefore, little systematic or quantitative work had been carried out on this interesting phenomenon. But now specific studies on a wide variety of biochemical, organic, and inorganic reactions under frozen conditions have been reported. Such studies have given rise to unusual experimental results and interesting theoretical speculations.(1) A. K. Balls and H. Lineweaver, Food Res., 3, 57 (1938).(2) (a) A. K. Ball, Ice Cold Storage, 41, 101 (1938); (b) Ckem.
The crystallization of 1, l'-binaphthyl from its racemic melt is an example of spontaneous generation of optical activity. The distribution of specific rotations in 200 individual samples varied from [alpha](D) = -218 degrees to [alpha](D) = +206 degrees with a mean of +0.14 degree and standard deviation of 86.4 degrees. This resolution into enantiomers is determined by chance development, with equal probability, of right- or left-handed crystallites; it can be controlled and made stereospecific by addition of dissymmetric compounds at low concentrations.
Tetracyclo[3.3.1.13.7.01..3]decane (i.e., 1,3-dehydroadamantane or DHA) and its 5,7-dimethyl derivative may be synthesized from the corresponding 1,3-dibromoadamantane compounds with sodium–potassium alloy in ether or heptane. These highly strained cyclopropyl compounds are very reactive towards free radical and electrophilic reagents. They homopolymerize 140–160° to thermally resistant, insoluble materials and spontaneously copolymerize with oxygen in solvents at room temperature. Reaction with bromine in ether at −70° yields an intermediate bromoadamantyloxonium tribromide which decomposes to 1-bromo-3-ethoxyadamantane on warming. Other rapid reactions of these strained 1,3-dehydroadamantanes are reported.
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