Derivatives of β-(Trimethylsilyl)alanine with SiCH2NH2, SiCH2OH, or SiCH2SH Functionality: Synthesis of the Silicon-Containing α-Amino Acids rac- and (R)-Me2Si(CH2R)CH2CH(NH2)COOH (R = NH2, OH, SH)†

The silicon-containing α-amino acids rac- and (R)-Me2Si(CH2R)CH2CH(NH2)COOH (1, R = NH2; 2, R = OH; 3, R = SH) were prepared in multistep syntheses and isolated as dihydrochlorides (rac-1, (R)-1) and hydrochlorides (rac-2, (R)-2, rac-3, (R)-3), respectively. 3,6-Diethoxy-2,5-dihydropyrazine (→ racemic compounds) and (R)-3,6-diethoxy-2-isopropyl-2,5-dihydropyrazine (→ (R)-enantiomers) served as starting materials. The identities of the β-(trimethylsilyl)alanine derivatives rac-1−rac-3 and (R)-1−(R)-3 were established by elemental analyses and NMR studies.