How can I convert d-altrose bond line view to Fischer projection?
1 Answer
The bond-line structure of D-altrose is
This structure gives no stereochemical information. It could represent any of the 16 stereoisomeric aldohexoses.
The wedge-dash structure of D-altrose is
Now we convert the wedge-dash to a Fischer projection.
(a) Arrange the molecule so that the chiral carbons and the longest continuous chain are in a vertical arrangement, with the aldehyde group at the top and the hydroxymethyl group at the bottom. Put crosses at C-2, C-3, C-4, and C-5.
(b) Put the OH group at C-2 on the correct side of the cross.
View the molecule from an angle that puts C-2 closest to our eye and C-1 at the top (the upper left). The OH group is on the left.
(c) Put the OH group at C-3 on the correct side of the cross.
View the molecule from the lower left. The OH group is on the right.
(d) Repeat at C-4, viewing from the upper left.
The OH group is on the right.
(e) Repeat at C-5, viewing from the lower left.
The OH group is on the right.
And we have the Fischer projection of D-altrose.
