Solution and Solid Phase Synthesis of Unusual a-Amino Acids From

added and the mixture stllred an additionai 15 min. The 2-neck 50 mL RBF was tilted
(see figure 6.la) to add the Wang Ser-OB0 carbarnate 6.33 (0.200 g, 0.14 mmol, 0.68
mrnovg) to the stirring mixture at -78OC. After 8 h at -78°C. DIPEA (1.41 mL. 8.2
mmol) was added and the mixture stirred an additional 2 h while warming to room
temperature. The solvent was removed under anhydrous conditions and copiously nnsed
with dry CH2C12, Et20 (2 x 25 d) then dried under high vacuum.
MAS 'H NlMR (Spin-Echo-6û ms): 6 9.71 (CHO), 3.91 (OB0 ester CH20). 0.80 (OB0
ester CH3).
6.4.9 Wang/TentaGe1 pHBa resin Thr(ket)-OB0 carbarnate, 6-35.
Oxalyl chloride (0.293 mL, 3.36 rnmol) was added to dry CHSl2 (20 rnL) in a 50 mL 2-
neck RBF and stirred under Ar at -78OC. DMSO (0.491 mL, 6.93 mmol) was quickly
added and the mixture stirred an additional 15 min. The 2-neck 50 rnL RBF was tilted
(see figure 6. la) to add the Wang Thr-OB0 carbamate 6.34 (0.320 g, 0.21 mmol, 0.64
mrnoUg) to the stirring mixture at -78°C. After 8 h at -78°C. DPEA (1.82 mL, 10.5
mmol) was added and the mixture stirred an additional 2 h while warrning to room
temperature. The solvent was removed under anhydrous conditions and copiously rinsed
with dry CH2C12, EtzO (2 x 25 mL) then dried under high vacuum.