The backbone of D-fructose consists of two C-atom triplets--one
symmetric, one asymmetric. The three C-atoms of the asymmetric triplet
have the same conformation as the three C-atoms of L-alanine.
The paper shows each of the ways in which the two triplets can join
end to end to form a di-triplet. It then examines each of the
di-triplets to see if it can accommodate an H2O-group on each of its
six C-atoms.
Out of thirty di-triplets, there are eight which are suitable as a
hexose backbone.
There are 640 different ways in which the H2O-groups can be arranged
on each of four di-triplets, 576 ways on one more, and 384 ways on
each of the remaining three.
This is presented in the fifty-page file SymLdiTriplets.pdf which
contains 46 figures and can be found on the "Files for sharing" page
of the website
http://homepage.mac.com/whitby/
