ABC26OR1088 · Goc and Stereochemistry
Subject: Organic Chemistry · Chapter: Goc and Stereochemistry · Topic: Goc & Stereochemistry – General · Exam: NET JUNE 2013 · Marks: 2 · Difficulty: Medium
The most stable conformations of 1, 2-difluoroethane and dl-2, 3-butanediol are
(a)
and [second sketch not cut — see note]
and [second sketch not cut — see note](b)
and 
and (c)
and 
and (d)
and 
and Answer
Answer (as printed): D
Explanation
• In case of F-CH2-CH2-F Gauche conformation is stable due to Gauche effect i.e. hyper conjugation. • Gauche effect refers to the phenomenon that the gauche conformer is energetically more stable than the anti-conformer in 1,2 dihaloethanes (X-CH 2-CH2-X) CSIR DEC 2013 |GOC & STEREOCHEMISTRY
Explanation as extracted from the printed page; notation may be imperfect.