Illustrated Glossary of Organic Chemistry
Gauche:
The relationship between two atoms or
groups
whose
dihedral angle
is more than 0
o
(i.e.,
eclipsed
) but less than 120
o
(i.e., the next
eclipsed
conformation
). A
conformation
which has one or more gauche interactions is can be called a gauche
conformation
.
The
anti-staggered
conformation
of
butane
has six gauche relationships.
This is a gauche
conformation
because the
methyl groups
are gauche.
This
conformation
has a total of six gauche relationships.
Related terms:
Torsional strain
,
Newman projection
,
bond rotation
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