Adjective
diastereoselective (comparative more diastereoselective, superlative most diastereoselective)
Of, pertaining to, or exhibiting diastereoselectivity
Aldrichimica Acta Volume 30 No 4 (pdf) from Sigma-Aldrich
This electronwithdrawing functionality not only inhibits the tendency of vinyldiazomethanes to rearrange to 3H-pyrazoles, but is also necessary to achieve highly diastereoselective cyclopropanations.