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Functionally substituted vinyl carbanions, 40. Synthesis of the basic structure of ezomycin A

✍ Scribed by Maier, Sibylle ;Preuss, Rainer ;Schmidt, Richard R.

Book ID
102902273
Publisher
John Wiley and Sons
Year
1990
Tongue
English
Weight
795 KB
Volume
1990
Category
Article
ISSN
0947-3440

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✦ Synopsis

Abstract

Direct 1‐C‐lithiation of the readily available 2‐phenylsulfinyl‐D‐galactals 3h, 1 leads to reactive intermediates, which on reaction with glyoxal monodiethyl acetal as electrophile yield compounds 7. Subsequent O‐benzylation of the unprotected hydroxy group, removal of the phenylsulfinyl group with Raney nickel, and diastereospecific 3‐hydrogen and 4‐hydroxy transfer provide a convenient entry into functionalized C‐β‐D‐galactopyranosides or 3,7‐anhydrooctoses 11, respectively. Acid‐catalyzed deacetalization and furanose formation with acetic anhydride/pyridine affords 3,7‐anhydrooctofuranoses‐(1,4) 14. The O‐acetylated D‐erythro‐L‐talo isomer (R)‐17 reacts with the cytidine derivative 18, leading to the ezomycin A basic structure 4.

📜 SIMILAR VOLUMES

Functionally substituted vinyl carbanion
Functionally substituted vinyl carbanions, 44. Synthesis of odd-numbered 13-crown-4 derivatives possessing a functional group and their application inC-lithiation of acrylates
✍ Jatzke, Harald ;Schmidt, Richard R. 📂 Article 📅 1991 🏛 John Wiley and Sons 🌐 English ⚖ 515 KB

## Abstract The synthesis of symmetrically hydroxy‐substituted 13‐crown‐ 4 derivatives 2 and 3 is reported. To this end, diol 7 is first deprotonated with potassium __tert__‐butoxide and then treated with ditosylate 6 in the presence of lithium perchlorate as a template. Base‐catalyzed addition of