diastereoisomer excess (diastereoisomeric excess)

Also contains definition of: percent diastereoisomer excess
https://doi.org/10.1351/goldbook.D01675
This is defined by analogy with
enantiomer excess
, as D1D2 [and the percent diastereoisomer excess as 100 (D1D2)], where the
mole
fractions of two
diastereoisomers
in a mixture or the fractional yields of two
diastereoisomers
formed in a reaction are D1 and D2 (D1+D2=1). The term is not applicable if more than two
diastereoisomers
are present. Frequently this term is abbreviated to d.e.
See:
diastereoisomerism
,
stereoselectivity
Source:
PAC, 1996, 68, 2193. (Basic terminology of stereochemistry (IUPAC Recommendations 1996)) on page 2205 [Terms] [Paper]