Title
Peptides containing gamma,delta-dihydroxy-L-leucine
Document Type
Article
Publication Date
6-5-2009
Abstract
(+/-)-Dehydroleucine was prepared and resolved by porcine kidney acylase. Under the conditions of the Sharpless asymmetric dihydroxylation (SAD), employing AD-mix-alpha, N alpha-carbobenzyloxy-(2S)-4,5-dehydroleucine methyl ester (16) gave rise to a 6.5:1.0 mixture of gamma-lactones 17, favoring the 4R configuration. Such carbamate-protected alpha-amino-gamma-hydroxylactones are not recommended as intermediates for peptide synthesis, since model studies showed that lactone 13 was unreactive toward amines. Moreover, the lactone ring could not be opened hydrolytically without epimerization at C alpha. N alpha-carbobenzyloxy-(2S)-4,5-dehydroleucine (22) was condensed with valine ethyl ester (19) to give dipeptide 23. Treatment of 23 with AD-mix-beta, under the SAD conditions, converted the dehydroleucine residue to gamma,delta-dihydroxyleucine with 4S configuration, as occurs in alloviroidin (3), a natural product isolated from Amanita suballiacea.
Publication Source (Journal or Book title)
The Journal of organic chemistry
First Page
4132
Last Page
6
Recommended Citation
Edagwa, B. J., & Taylor, C. M. (2009). Peptides containing gamma,delta-dihydroxy-L-leucine. The Journal of organic chemistry, 74 (11), 4132-6. https://doi.org/10.1021/jo900459f