A FACILE SYNTHESIS OF TERT-BUTYL 5,5-TETRAMETHYL-1,3,2-DIOXABOROLAN-2-YL)PROPIONATE - AN ORTHOGONALLY PROTECTED BORONIC ACID ANALOG OF ASPARTIC-ACID

Citation
Gk. Hsiao et Dg. Hangauer, A FACILE SYNTHESIS OF TERT-BUTYL 5,5-TETRAMETHYL-1,3,2-DIOXABOROLAN-2-YL)PROPIONATE - AN ORTHOGONALLY PROTECTED BORONIC ACID ANALOG OF ASPARTIC-ACID, Synthesis, (7), 1998, pp. 1043-1046
Citations number
14
Categorie Soggetti
Chemistry Inorganic & Nuclear
Journal title
ISSN journal
00397881
Issue
7
Year of publication
1998
Pages
1043 - 1046
Database
ISI
SICI code
0039-7881(1998):7<1043:AFSOT5>2.0.ZU;2-E
Abstract
tert-Butyl -(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)prop an ortho gonally protected analog of aspartic acid wherein the side chain carbo xylic acid is replaced with a boronic acid moiety, was conveniently sy nthesized by alkylation of N-(diphenylmethylene)glycine tertbutyl este r with pinacol (chloromethyl)boronate as the key step. After selective cleavage of the tert-butyl ester this unnatural amino acid was couple d with L-isoleucinamide using a mixed a anhydride method. The two dias tereomers of the resulting dipeptides were separated by reversed phase HPLC and their absolute configurations were established by oxidizing the boronic acids to the corresponding hydroxy groups followed by NMR and HPLC correlation with authentic Cbz-L-Ser-L-Ile-NH2.