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- Titel:
SN1-Type Substitution Reactions of N-Protected ss-Hydroxytyrosine Esters: Stereoselective Synthesis of ss-Aryl and ss-Alkyltyrosines
- Dokumenttyp:
- Journal Article
- Autor(en):
- Wilcke, D.; Herdtweck, E.; Bach, T.
- Abstract:
- The title compounds were prepared by aldol reaction of anisaldehyde and the respective N,N-dibenzyl glycinates. Deprotection of the nitrogen atom with Pearlmans catalyst delivered the unprotected beta-hydroxytyrosine esters, which were further N-protected as N,N-phthaloyl (Phth) and N-fluorenylmethylcarbonyloxy (Fmoc) derivatives. The FriedelCrafts reaction with various arenes was studied employing these alcohols as electrophiles. It turned out that the facial diastereoselectivitiy depends on the nitrogen protecting group and on the ester group. The unprotected substrates (NH2) gave preferentially syn-products but the anti-selectivity increased when going from NHFmoc over NPhth to NBn2. If the ester substituent was varied the syn-preference increased in the order Me
95:5). Upon acetylation of the latter compound to the respective acetate, Bi(OTf)3-catalyzed alkylation reactions became possible, in which silyl enol ethers served as nucleophiles. The respective alkylation products were obtained in high yield and with excellent anti-selectivitiy (anti/syn=95:5). - Kongresstitel:
- ISI Document Delivery No.: 947OY Times Cited: 1 Cited Reference Count: 88 Wilcke, David Herdtweck, Eberhardt Bach, Thorsten Deutsche Forschungsgemeinschaft [Ba 1372-12]; graduate college NanoCat; TUM Graduate School This project was supported by the Deutsche Forschungsgemeinschaft (Ba 1372-12), by the graduate college NanoCat (scholarship to D. W.), and by the TUM Graduate School. The help of Andrea Schmidt (undergraduate research participant) and of Takuya Ishikawa (exchange student) is grate... »
- Zeitschriftentitel:
- Chemistry-an Asian Journal
- Jahr:
- 2012
- Band / Volume:
- 7
- Heft / Issue:
- 6
- Seitenangaben Beitrag:
- 1372-1382
- Volltext / DOI:
- doi:10.1002/asia.201101016
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