The molecule is a mannarate(2-) that is the dianion obtained by the deprotonation of the carboxy groups of L-mannaric acid. It is a conjugate base of a L-mannarate(1-). It is an enantiomer of a D-mannarate(2-).
(2R,3R,4R,5R)-2,3,4,5-tetrahydroxyhexanedioate