ABC26OR0008 · General Organic Chemistry
Subject: Organic Chemistry · Chapter: General Organic Chemistry · Topic: Nomenclature Polycyclics · Exam: CSIR-NET JUNE 2011 · Marks: 2 · Difficulty: Medium
The IUPAC name of the following compound is 
(a)(R)-3- (prop-2-enyl) hex-5-ynoic acid
(b)(S)-3- (prop-2-enyl) hex-5-ynoic acid
(c)(R)-3- (prop-2-enyl) hex-5-enoic acid
(d)(S)-3- (prop-2-ynyl) hex-5- enoic acid
Answer
Answer (as printed): D
Explanation
While numbering a compound, the functional group is given preference compared to the other substituents. Thus, numbering begins from carboxylic acid carbon and proceeds in an ascending order following the longest trail of carbon atoms. The groups attached to the longest trail of carbon atoms (here, 6) act as substituents. At carbon 3, prop-2-ynyl is the substituent.
Explanation as extracted from the printed page; notation may be imperfect.