Does a Fisher projection provide any extra information compared to a bond line view?
1 Answer
Yes, a Fischer projection gives the absolute stereochemistry of a molecule. A bond-line view provides none.
The bond-line structure of glucose is
It tells you only which atom is connected to which.
It gives no stereochemical information.
It could represent any of the 16 stereoisomeric aldohexoses.
The Fischer projection of D-glucose is
At first glance, this appears to give no more information.
But we must remember that in a Fischer projection the horizontal bonds are coming out of the paper and the vertical bonds are behind the paper.
There is only one molecule that can have this particular combination of wedges and dashes: D-glucose.
Conclusion: A Fischer projection provides more information than a bond-line formula.
