A Guidebook to Mechanism in Organic Chemistry

Addition to Carbon-Oxygen Double Bonds

Of

H—C-e-C—H

H,0

O OH

II I

H—C—C—H

AH

CI OH

I I

Cl—C—C—H

A OH

o
(III) (IV)
(IV) is ninhydrin, the well-known colour reagent for the detection and
estimation of a-amino acids. The hydrates are probably further
stabilised by hydtagpn bonding between the hydroxyl groups and the
ele**»negative oxy§gn or chlorine atoms attached to the adjacent
a-carbon: u

</ \
II I
H—C- -C—H
I
OH
(ii) ROH
Aldehydes with alcohols, in the presence of dry hydrogen chloride,
yield acetals: H
O OH EOH
II ROH
R'—C—H *== R

H© |

-C—H ?== R'—C—H

OR

| -H«

R'—C—H ^=

I

OR

OR

• •
  H
  ®OR

'AR

1-H,°

R'-

R OH e

H R—C—H

OR OR