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

6.4.5 Wan&TenîaGel pHBB resin imidazolide, 6 3.
N,N'-Carbony1diimidau,ie 6.28 (0.60 g, 3.7 mmd) was combined with Wang resin
(1.0 g, 0.74 mmo1,0.74 mmollg) then taken up in dry THF (10 mL). Aner 4 h, the
mixture was poured into a sintered giass h e l and the sdvent removed under
vacuum. The resin was washed Pltematively with TEIF (5 x 25 mL) and CH2Cl2 (5 x
25 mL) then with EtzO (2 x 25 mL) and dried under high vacuum.
IR (Dr) 1755 cm-'. Anal. calcd for N, 0.94% corresponds to 98% substitution.
604.6 WanflentaGeI pHBe resin p-nitrophen01 carbonate, 6.31.
p-Nitrophenolchloroformate 6.29 (1.3 1 g, 6.5 mmol) was added to a stimng mixture of
Wang resin (1.75 g, 1.3 mmol, 0.74 mmoVg) in N-methyl morpholine (1.43 mL, 13.0
mmol) and dry CHg12 (30 m.) whilst under Ar at 0°C. The mixture was allowed to
reach ambient temperature and after 12 h the resin was filtered off and washed with
CHzClz (5 x 50 mL), Et20 (2 x 50 mL) and dried under high vacuum.
IR (KBr) 1761 cm-'. And. calcd for N, 0.92% corresponds to 99% substitution.
6.4.6 WanflentaGel PBB' rosis Ser-OB0 carbamate, 6.32.
Ser-OB0 6.26 (0.600 g, 3.17 mmol) and DMAP (O. 15 g, 1.26 mmol) were dissolved in
N-methyl pyrrolidinone (5 mL) and N,O-bis(trimethylsily1)acetamide (0.94 mL, 3.8
mmol) to which Wang p-nitrophenol carbonate resin 6.31 (1.00 g, 0.63 mmoWg) was
added. The mixture was stirred for 24 h before the resin was filtered off and the resin