Which of the following generla rules for switching ligands or rotaing Fischer structures is incorrect?

Options

A. An even number of switches results in no change in the configuration
B. An odd number of switches changes the configuration to that of the enantiomer
C. The structure cannot be rotated out of the plane of the paper
D. The structure can be rotated in the plane through `90^(@)`

Answer

D

Explanation

Any rotation of Fisher projections that interconverts horizontal and vertical ligands is not allowed. Hence, the structure can be rotated in the plane through `180^(@)` or its multiples but not through `90^(@)`