General Procedure B (cleavage from resin). This procedure was performed as previously published. For confirmation of completion of the reaction, dried resin (2-3 mg) was shaken with the cleavage solution (CH2Cl2/TFA, 95/5 v/v; 100 µL/mg) for 1 h at room temperature. After filtration, the solution was adjusted to 1 mL with MeCN and analyzed by HPLC.