Silicon-Containing Amino Acids and Peptides. Asymmetric Synthesis of (Trialkylsilyl)alanines

Synthesis of Silaproline, a New Proline Surrogate

“…[13] In this case, TMS-Ala is prepared in both enantiomeric forms by asymmetric synthesis starting from Schöllkopf's reagent and chloromethyltrimethylsilane. Other syntheses of TMS-Ala have been described in the literature, [14][15][16] and a more recent report concerns γ-silylated amino acids. [17] To the best of our knowledge, the other well-known methods for asymmetric synthesis of amino acids (Williams, [18] Oppolzer, [19] hydroxypinanone [20] methods) have not been applied to silicon-containing amino acids.…”

“…(R)-N-(tert-Butoxycarbonyl)silaproline (14): A solution of R-12 (240 mg, 0.879 mmol) in MeOH (3 mL), cooled to 0-5°C was slowly treated with a solution of KOH 2  (1.3 mL, 2.637 mmol). …”

Chemistry of Silicon‐Containing Amino Acids

“…The following are examples of acidic removal of Boc groups from trimethylsilylalanines 2 [16], silylphenylalanine 4 [48,49], and silylprolines 6 and 7 [43,50]. Hydrogenolysis of Cbz groups on silicon-substituted prolines 6 has been reported [37].…”

“…Hydrogenolysis of Cbz groups on silicon-substituted prolines 6 has been reported [37]. Basic removal of Fmoc groups from trimethylsilylalanine 2 is firmly established [16,20,43]. acid to give products with comparable activity has suggested an isosteric relationship (Scheme 6.13).…”

How to build optically active?-amino acids

“…The corresponding bromide was subjected to an SN2 azide displacement reaction with TMGA, giving a single diastereoisomer (Xiang et al, 1995;Walkup et al, 1995) (Fig. 25).…”