23-butanediol, 2,3-Dimethyl

Would you expect the OH stretching frequencies in 2,3-dimethyl-2,3-butanediol to be shifted from the value in tert-butyl alcohol, even in dilute solution. Identify the OH stretching frequencies in the diol and compare them to tert-butyl alcohol. Rationalize your observations by comparing the geometry of the diol with those of tert-butyl alcohol and tert-butyl alcohol dimer. 

Because reductions by metals often occur as one-electron processes, radicals are involved as intermediates. When the reaction conditions are adjusted so that coupling competes favorably with other processes, the formation of a carbon-carbon bond can occur. The reductive coupling of acetone to form 2,3-dimethyl-2,3-butanediol (pinacol) is an example of such a process. 

About 30 years ago, an enthalpy of formation was reported for 3,3,4,4-tetramethyl-l,2-dioxetane . Both by direct microcalorimetric combustion measurements of the neat solid and by reaction calorimetry (of the solid itself, and in acetone solution to form acetone), a consensus value was derived. Now, is the enthalpy of formation plausible , notwithstanding the very large error bars Consider reaction 6 for the dioxetane that produces 2,3-dimethyl-2,3-butanediol . The liquid phase enthalpy of reaction is —329 kJmoU. It is remarkable that this value is compatible with that for the dialkyl peroxides, ca —335 kJmoU, despite the ring strain that might be expected. 

The Pinacol Coupling of acetone gives 2,3-dimethyl-2,3-butanediol which is also known as pinacol and the source of the name of this reaction ... 

Exercise 16-43 How could one dehydrate 2,3-dimethyl-2,3-butanediol to 2,3-di-methyl-1,3-butadiene without forming excessive amounts of 3,3-dimethyl-2-butanone in the process ... 

The pinacol rearrangement is a useful reaction that proceeds via a carbocation rearrangement. Treatment of 2,3-dimethyl-2,3-butanediol, also known as pinacol, with acid results in the formation of a ketone, pinacolone ... 

The alditol crystal structures are conformationally homogeneous. The cocrystallization of different conformers of the same molecule is not common, but sufficient examples are known, especially in hydrogen-bonded crystal structures, for it to be a phenomenon with which crystallographers are familiar. It occurs when there is a population of conformers in solution, all of which have similar energies. A classical example is that of 2,3-dimethyl-2,3-butanediol (pinacol)... 

Jeffrey GA, Robbins A (1978) 2,3-Dimethyl-2,3-butanediol (pinacol). Acta Cryst B34 3817-3820... 

Dimethyl-2,3-butanediol (pinacol) (2.12) on treatment with H2SO4 generates 3,3-dimethyl-2-butanone, commonly known as pinacolone (2.13). Pinacol itself is produced by magnesium reduction of acetone, probably by way of a ketyl intermediate. 

Dimethyl-2,3-butanediol has the common name phuicol. On heating with aqueous acid, pinacol rearranges to pitlacolone, 3,3-dimethyl-2-butanone. Suggest a mechanism for this reaction. 

C6H140 ethyl butyl ether 628-81-9 -103.00 0.9993 2 9395 C6H2608 2,3-dimethyl-2,3-butanediol hexahydrate 6091-58-3 15.00 0.9670 1... 

As catalytic tests four reactions, isomerization of 1-butene and methyloxirane, dehydration of 2-propanol and the pinacol rearrangement of 2,3-dimethyl-2,3-butanediol were used. 

Upon treatment with mineral acids, 2,3-dimethyl-2,3-butanediol (often called pinacol) is converted into methyl terf-butyl ketone (often called pinacolone). The... 

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