Enantioselective synthesis of α-branched α-amino acids with bulky substituents

✍ Scribed by Studer, Armido ;Seebach, Dieter

• Book ID: 102903065
• Publisher: John Wiley and Sons
• Year: 1995
• Tongue: English
• Weight: 712 KB
• Volume: 1995
• Category: Article
• ISSN: 0947-3440
• DOI: 10.1002/jlac.199519950231

✦ Synopsis

Abstract

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 (PhCH~2~/Et, PhCH~2~/i‐Pr, PhCH~2~/CH~2~C~6~H~11~) 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.