13. Alcohols and Carbonyl Compounds

Predict the major products of the following reactions, including stereochemistry where appropriate.

(e) cyclopentylmethanol + Na₂Cr₂O₇/H₂SO₄

(f) cyclopentanol + HCl/ZnCl₂

(g) n-butanol + HBr

Give the structure of the principal product(s) when each of the following alcohols reacts with (1) Na₂Cr₂O₇/H₂SO₄, (2) PCC

d. 1-methylcyclohexan-1,4-diol

Predict the products of the reactions of the following compounds with:

1. chromic acid or excess sodium hypochlorite with acetic acid.

2. PCC or NaOCl (1 equivalent) with TEMPO.

e. cyclohexane

Predict the major products of the following reactions.

(a)

Identify the alcohols that would undergo oxidation to produce the following carbonyl compounds.

(b)

The intermediates for the Swern oxidation, a reaction introduced in Section 13.9.4, are shown. Provide the arrow-pushing mechanism that rationalizes the formation of each intermediate and the final product(s).

Propose a mechanism to explain how dimethyl sulfoxide and oxalyl chloride react to form the dimethylchlorosulfonium ion used as the oxidizing agent in the Swern oxidation.

What is the product of the reaction?

Predict the product of the following reactions.

(a)

In Chapter 13, we explain how to convert secondary alcohols into ketones using a mild oxidation reaction. When the following enantiomerically pure and optically active secondary alcohol is submitted to these reaction conditions, the product is optically inactive. Explain this observation.

The following reaction involves a starting material with a double bond and a hydroxy group, yet its mechanism resembles a pinacol rearrangement. Propose a mechanism, and point out the part of your mechanism that resembles a pinacol rearrangement.

Give the structure of the principal product(s) when each of the following alcohols reacts with (3) DMP and (4) 1 equiv NaOCl-TEMPO.

d. 1-methylcyclohexan-1,4-diol

Lipoic acid is often found near the active sites of enzymes, usually bound to the peptide by a long, flexible amide linkage with a lysine residue.

(a) Is lipoic acid a mild oxidizing agent or a mild reducing agent? Draw it in both its oxidized and reduced forms.

(b) Show how lipoic acid might react with two Cys residues to form a disulfide bridge.

(c) Give a balanced equation for the hypothetical oxidation or reduction, as you predicted in part (a), of an aldehyde by lipoic acid.

Predict the product(s) that would result when molecules (a)–(p) are allowed to react under the following conditions: (xi) HOCl, H₂O (xii) HIO₄ If no reaction occurs, write 'no reaction.'

(c)

Show how you would make each compound, beginning with an alcohol of your choice.

(d)

(e)

(f)