Deprotection of t-Butyl Esters of Amino Acid Derivatives by Nitric Acid in Dichloromethane
作者:Paolo Strazzolini、Massimo Scuccato、Angelo G Giumanini
DOI:10.1016/s0040-4020(00)00280-5
日期:2000.5
selected N-Z-derivatives of natural amino acidesters was investigated. The method was found to work effectively with alanine, phenylalanine, serine and the dipeptide aspartame, but the reagent brought about a number of unwanted transformations with tyrosine, methionine and tryptophan. Suitable protection of functions present in the latter ones allowed selective ester dealkylation, but tyrosine underwent
The asymmetric conjugateaddition of arylboronic acids to N-phthalimidodehydroalanine 1i catalyzed by Rh(I)/L1a enables the facile preparation of chiral functionalized phenylalanines. The reaction proceeds by a conjugateaddition and enantioselective protonation cascade, affording a rhodium enolate that undergoes re-face protonation. The reaction tolerates various arylboronic acids and can be used