Write the structure of the major organic product obtained by Hydroboration–oxidation of ea...

Write the structure of the major organic product obtained by Hydroboration–oxidation of each of the following alkenes:

(a) 2-Methylpropene

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(b) cis-2-Butene

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(c)

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(d) Cyclopentene

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(e) 3-Ethyl-2-pentene

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(f) 3-Ethyl-1-pentene

Sample Solution (a) In Hydroboration–oxidation, H and OH are introduced with a regioselectivity opposite to that of Markovnikov’s rule. In the case of 2-methylpropene, this leads to 2-methyl-1-propanol as the product.

Hydrogen becomes bonded to the carbon that has the fewer hydrogens, hydroxyl to the carbon that has the greater number of hydrogens.