Choosing the database version and probability distribution
Choosing the database version
The parameters used to calculate DP4 are taken from a database of calculated shifts maintained by the Goodman group. Later versions of the database are based on a greater number of molecules and so are recommended for best results.
However, if you wish to use an earlier version of the database, for example for consistency with earlier calculations, you can select the database version using the list at the top left of the applet.
The "DP4-original" database contains the values used in the journal article on DP4 (manuscript submitted), and later versions are listed in increasing version number.
Choosing the probability distribution
DP4 can be calculated assuming either a normal distribution or a t-distribution for the error in any individual calculated shift. We recommend using the t-distribution because we have found that it is less susceptable to overstating the probability. However, you can choose to carry out the calculation using the normal distribution of you wish. More information can be found in the journal article on DP4 (manuscript submitted).
Once you have selected a database and distribution, or chosen to use the defaults, proceed to:
Assigning Stereochemistry to Single Diastereoisomers by GIAO NMR Calculation: The DP4 Probability
S. G. Smith and J. M. Goodman J. Am. Chem. Soc. 2010, Accepted