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

63 Summ
Attachrnent of Ser-OB0 ester and Thr-OB0 ester ont0 the solid phase via a
carbarnate linker allowed for the oxidation and subsequent Grignard addition of various
nucleophiles towards the synthesis of p-substituted-B-hydroxy-a-amino acids. Moderate
diastereoselectivity for Grignard addition was observed to give predominantly the threo
isomer. Good overall yields (19-41 %) were achieved over six steps after purification by
cation exchange
The synthesis of p-hydroxy-a-amino acids on the solid phase has been shown to
possess similar characteristics
occurrence of racemization.
To our knowledge, this
arnino acids on the solid phase.
as solution phase chemistry, albeit with an increased
0
represents the fmt report of P-substituted-p-hydroxy-a-