To better understand chemical behavior of Ala B reagents, we conducted in silico conformational analysis of three representative Ala B structures in the form of Pin and Pai esters (Table ). Two Lewis basic sites located either at the α-amine (such as amides or carbamates) or the carboxylic acid (and its derivatives) can compete for boron's empty p orbital. Computational data indicate that both Pin and Pai esters prefer structures 21 and 22 over other conformers not stabilized by direct C=OàB interactions. Among two boracycles 21 and 22, five-membered isomers 22 are favored for all computed structures with the carboxylate ions existing almost exclusively in the cyclic form 22. Larger pinanediol groups are more efficient in shielding the boron center, which is also reflected in lower stabilization energies among the two isomers (entries 1-3 vs. 4-6). This study also allowed us to evaluate the effects of intramolecular carbonyl activation on acidity of α-protons (Table ). In each case, the α carbonyl protons carry increased positive charge consistent with our observations that epimerization can be observed for some Ala B amino acids. Interestingly, boron coordination has little effect on the computed atomic charges of the carbonyl group. However, intramolecular activation of the boron towards transmetalation becomes important in the subsequent studies on Pd-catalyzed C-C coupling of these C(sp 3 ) nucleophiles (vide infra).