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Please login to access the full content or check if you have access via2.2.11.5 (S)-Cleonin by Titanium-Catalyzed Cyclopropanation
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Garve, L. K. B.; Werz, D. B., Science of Synthesis: Metal-Catalyzed Cyclization Reactions, (2016) 2, 94.
(S)-Cleonin (140), an amino acid with a cyclopropanol substructure, is the key component of the very complex antitumor agent cleomycin. By making use of the Kulinkovich reaction (see Section 2.2.10) it is facile to prepare this important cyclopropane derivative from (R)-serine (137). Cyclopropanol 139 is formed from the methyl ester of N-benzyloxycarbonyl serine acetonide 138 under common Kulinkovich conditions employing a Grignard reagent and substoichiometric amounts of titanium(IV) isopropoxide (Scheme 47).[104] Acetonide removal, followed by oxidation of the primary alcohol, and benzyloxycarbonyl cleavage furnish the non-proteinogenic amino acid (S)-cleonin (140).
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References
| [104] | Meeeeeee, M.; Meeee, M. M.; Meeeeeeeee, M.; Meeeee, M., Mee. Meee., (8888) 8, 8888. |
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