Enantioselective synthesis of benzylic stereocentres via Claisen rearrangement of enantiomerically pure allylic alcohols: preparation of (R)- and (S)-3-methyl-2-phenylbutylamine
โ Scribed by Elisabetta Brenna; Claudio Fuganti; Francesco G. Gatti; Massimo Passoni; Stefano Serra
- Book ID
- 104359953
- Publisher
- Elsevier Science
- Year
- 2003
- Tongue
- English
- Weight
- 145 KB
- Volume
- 14
- Category
- Article
- ISSN
- 0957-4166
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โฆ Synopsis
The Johnson-Claisen rearrangement of enantiopure allylic alcohols in triethylorthopropionate is the key step for the preparation of chiral molecules with benzylic stereogenic carbon atoms bearing an isopropyl moiety. The synthetic procedure is applied to the preparation of (R)-and (S)-3-methyl-2-phenylbutylamine.
๐ SIMILAR VOLUMES
## Abstract The titanium derivative 2 of the bislactim ether 1 of cyclo(โLโValโGlyโ) reacts with aldehydes and ketones 3 highly diastereoselectively to give the __syn__โaddition products 4. Upon hydrolysis with diluted trifluoroacetic acid the compounds 4 yield besides methyl Lโvalinate the (2__R__
The titanium derivative 4a of the bislactim ether l a from cyclo-(L-Val-Gly) reacts with + m a t u r a t e d aldehydes 5 exclusively by 1.2-addition in a highly diastereowlective mode to give virtually only the (2R,l'S) diastereomers of type 6. Upon hydrolysis these furnish the methyl (2R,3S)-thrm-2