Amino acids, α-branched
Highly hindered amides
Hydrolysis of amino acid amides
Phenylalanine, 2-ethyl-, 2-i-propyl- and 2-cyclohexylmethyl-
Wiley InterScience Backfile Collection 1832-2000
Chemistry and Pharmacology
Enantiopure 5,5-disubstituted t-butyl 2-t-butyl-3-methyl-4-oxoimidazolidine-1-carboxylates readily available by diastereoselective double alkylation of the parent compound (Boc-BMI) can be converted to α-branched α-amino acids with two bulky substituents (PhCH2/Et, PhCH2/i-Pr, PhCH2/CH2C6H11) in four simple steps: hydrolysis to the amino acid amides, N-benzoylation, cleavage of the amino acid amide group, and debenzoylation (Scheme 3, products 6-10, overall yields 〉50%). This procedure constitutes an extension of the scope of amino acid synthesis from (R)- and (S)-Boc-BMI.
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