Question

How can I draw Fischer projections from Haworth?

Answer 1

Let's start with the Haworth projection of D-glucose.

Note that

• The wedges and the thick line indicate that C-2 and C-3 are closer to the observer.
• C-1 and C-4 are in the plane of the paper.
• O and C-5 are behind the paper.
• The groups below the plane of the ring are on the right hand side of a Fischer projection.

To convert the Haworth projection to a Fischer projection, you mentally cleave the C-O bond and orient the new chain with C-1 at the top.

If the `"CH"_2"OH"` group is on the top in the Haworth structure, the OH group on C-5 is on the right.

If the `"CH"_2"OH"` group is on the bottom in the Haworth structure (an L sugar), the OH group on C-5 is on the left.