3- Methyl-2-butanol reaction with hydrogen chloride

Let us take as an example ( — )-2.-methyl-l-butanol (the enantiomer found in fusel oil) and accept, for the moment, that it has configuration III, which we would specify S. We treat this alcohol with hydrogen chloride. and obtain the alkyl chloride, l-chloro-2-methylbutane. Without knowing the mechanism of this reaction, we can see that the carbon-oxygen bond is the one that is broken. No bond to the chiral center is broken, and therefore configuration is retained, with... 

Reactions in which bonds to chiral centers are not broken can be used to get one more highly important kind of information the specific rotations of optically pure compounds. For example, the 2-methyl-1-butanol obtained from fusel oil (which happens to have specific rotation -5.756°) is optically pure—like most chiral compounds from biological sources—that is, it consists entirely of the one enantiomer, and contains none of its mirror image. When this material is treated with hydrogen chloride, the l-chloro-2-methylbutanc obtained is found to have specific rotation of 4-1.64°. Since no bond to the chiral center is broken, eveyy... 

Assuming that the rate-determining step in the reaction of 2-methyl-2-butanol with hydrogen chloride to give 2-chloro-2-methylbutane is unimolecular, write an equation for this step. Use curved arrows to show the flow of electrons. 

The reaction of formaldehyde with alkenes is of industrial interest and has been extensively studied. Reaction of excess formaldehyde as formalin with an alkene and aqueous acid gives 1,3-dioxanes (2) in 40-90% yield. Reaction of 2-butenes with paraformaldehyde and hydrogen chloride at -65 C gives a mixture of diastereomeric y-chloro alcohols rich in the isomer formed by trans addition to the alkenyl double bond. For example frans-2-butene gives an 85 15 mixture of erythro- and fAreo-3-chloro-2-methyl-1-butanol (equation 2). Reaction of 1-alkenes under similar conditions gives 3-alkyl-4-chlorotet-rahydropyrans (5) in 50-80% yield (Scheme 2). Initial reaction occurs via addition of formaldehyde to the terminal carbon of the double bond, followed by loss of a proton to give the 3-alken-l-ol. Reaction of... 

METHYL-l-BUTANOL (primary) (123-51-3) Forms explosive mixture with air (flash point 109°F/43°C). Violent reaction with strong oxidizers, reducing agents, hydrogen trisulfide. Incompatible with acid anhydrides, acid chlorides, aliphatic amines, caustics, isocyanates, nitric acid, sulfuric acid. Attacks some plastics, rubber, and coatings. 

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