The D-site loses this structure due to distortion by Glu and Asp side chains in the mechanism of lysozyme. The Zimmerman-Traxler model predicts the aldol reaction's stereochemistry by assuming the transition state has this specific structure (15[1])and analyzing (15[1])the steric interactions. (15[1])Transition states with this structure are thermodynamically favored for [3+3]-rearrangements like the Claisen and (*) Cope rearrangements. The Newman projection for this conformation is fully staggered, while it is fully gauche for a different conformation that experiences ■END■