Concise and diastereoselective approach to syn- and anti-N-tosyl-a-hydroxy b-amino acid derivatives
نویسندگان
چکیده
The methyl diazoacetate and aryl (N-tosyl)imines can be transformed into syn or anti a-hydroxy b-amino esters with high diastereoselectivities in three steps: the base promoted nucleophilic condensation of the methyl diazoacetate and aryl (N-tosyl)imines to give b-(N-tosyl)amino a-diazoesters, followed by oxidation with Oxone to generate a-oxo esters, which were reduced with NaBH4 to yield the anti-N-tosyl-a-hydroxy b-amino ester, or hydrogenated with Pd/C (10%) as the catalyst to yield corresponding syn isomer, both in high diastereoselectivity. q 2005 Elsevier Ltd. All rights reserved. Scheme 1.
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