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

off the resin under classical conditions and N-debenzylated to give the 3-substituted
prolines 6.14. However, no comrnents were made regarding the final yield or purity of
6.14 after cleavage off the min.
9 LDA. THF, -78°C
I
Scheme 6.6
"Y $ II- O
"^O
2) ZnBr2
6.1 1 O%
6.1 2
Nu=PhSH, tryptamine, pN&phenol
lb
Various nucleophiles have been added to pyroglutamate 6.15 attached to Wang
resin to give glutamate derivatives 6.16 which were cleaved off the resin with TFA
(Scheme 6.7)." The use of a catalyst (KCN) was required with most of the reactions
occumng in good yield and high purity.
O
NU. KCN., &au
O Nu=ROH. RRNH.
Scheme 6.7
T A ;. "02c,dNu
NHBoc NHBoc