How to find total number of isomers in a given compound?
There isn't any formula for structural isomers. But there are formulas for stereo isomers. If there are n chiral carbons in a molecule, then the following two cases may arise.
case 1: The ends of the molecule are asymmetric. In this case the number of structural isomers are 2n2n and all of them are optically active.
case2: The ends of the molecule is symmetric. Following two cases may arise
case 2a. n is even. In this case number of optically active form=2(n−1)2(n−1) Number of meso isomers is 2(0.5n−1)2(0.5n−1) and the total number of stereo isomer is the summation of these two.
case 2b. n is odd. In this case total number of stereo isomer is 2(n−1).2(n−1). Number of meso isomers is 2(0.5n−0.5)2(0.5n−0.5) and the number of optically active forms is the difference of these two
Hope that was useful.
There isn't any formula for structural isomers. But there are formulas for stereo isomers. If there are n chiral carbons in a molecule, then the following two cases may arise.
case 1: The ends of the molecule are asymmetric. In this case the number of structural isomers are 2n2n and all of them are optically active.
case2: The ends of the molecule is symmetric. Following two cases may arise
case 2a. n is even. In this case number of optically active form=2(n−1)2(n−1) Number of meso isomers is 2(0.5n−1)2(0.5n−1) and the total number of stereo isomer is the summation of these two.
case 2b. n is odd. In this case total number of stereo isomer is 2(n−1).2(n−1). Number of meso isomers is 2(0.5n−0.5)2(0.5n−0.5) and the number of optically active forms is the difference of these two
Hope that was useful.
