Scheme 1. Synthesis of Phenethyl Esters and Amides.

Reagents and conditions: (a) 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide, hydroxybenzotriazole, N,N-diisopropylethylamine, MeCN, rt, 18 h, 36–57%; (b) benzotriazo-1-yl-oxytripyrrolidinophosphonium hexafluorophosphate, N,N-diisopropylethylamine, DCM, rt, 18 h, 69–93%; (c) 10% TFA in DCM (v/v), rt, 2 h, 42–97%. 2 was prepared as described previously.²¹