Development of an Asymmetric Hydrogenation Route to (S)-N-Boc-2,6-dimethyltyrosine

摘要

An improved, simpler and potentially more economical route to (S)-N-Boc-2,6-dimethyltyrosine 1, based on a previously published route, is presented. Key modifications were to prepare the dehydroaminoacid hydrogenation substrate 6 in a one-pot process directly from serine methyl ester and 4-iodo-3,5-dimethylphenyl acetate 4 and to identify a significantly more active asymmetric hydrogenation catalyst that allowed a 5-fold reduction in catalyst loading.