13. Alcohols and Carbonyl Compounds

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

(d)

(e)

(f)

Draw a mechanism for the following oxidation reactions.

(b)

What is the product of the reaction?

What is the product of the reaction?

What is the product of the reaction?

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.

What is the major product(s) of each of the following reactions?

c.

What is the major product(s) of each of the following reactions?

h.

Two unknowns, X and Y, both having the molecular formula C₄H₈O, give the following results with four chemical tests. Propose structures for X and Y consistent with this information.

We have covered several oxidants that use a multi-valent atom (Cr, Cl, S, or I) as their active species, going from a higher oxidation state before the oxidation to a lower oxidation state after oxidizing the alcohol. Draw the Lewis structures of the following atoms, before and after the oxidation of an alcohol to a ketone or aldehyde. How many bonds to oxygen does each atom have before and after the oxidation?

a. the Cr in chromic acid

b. the Cl in sodium hypochlorite

c. the S in the Swern oxidation

Under normal circumstances, tertiary alcohols are not oxidized. However, when the tertiary alcohol is allylic, it can undergo a migration of the double bond (called an allylic shift) and subsequent oxidation of the alcohol. A particularly effective reagent for this reaction is Bobbitt's reagent, similar to TEMPO used in many oxidations. (M. Shibuya et al., J. Org. Chem., 2008, 73, 4750.)

Show the expected product when each of these 3° allylic alcohols is oxidized by Bobbitt's reagent.

(a)

(b)

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.

a. cyclohexanol

b. 1-methylcyclohexanol

c. cyclopentylmethanol

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

(n) sodium ethoxide + 2-methyl-2-bromobutane

(o) octan-1-ol + DMSO + oxalyl chloride

(p) 4-cyclopentylhexan-1-ol + DMP reagent

Give the structure of the principal product(s) when each of the following alcohols reacts with (1) Na₂Cr₂O₇/H₂SO₄, (2) PCC, (3) DMP, and (4) 1 equiv NaOCl-TEMPO.

a. octan-1-ol

b. octan-3-ol

Predict the products you expect when the following starting material undergoes oxidation with an excess of each of the reagents shown below.

a. chromic acid

b. PCC (pyridinium chlorochromate)

c. sodium hypochlorite/acetic acid