Synthesis of allylsilane-containing amino acids via the Claisen rearrangement

✍ Scribed by Mustafa Mohamed; Michael A Brook

• Publisher: Elsevier Science
• Year: 2001
• Tongue: French
• Weight: 69 KB
• Volume: 42
• Category: Article
• ISSN: 0040-4039
• DOI: 10.1016/s0040-4039(00)01962-6

✦ Synopsis

The Claisen rearrangement of N-BOC-glycinate esters 1a-1d led to the formation of a-allylsilane-functionalized amino acids 2-3 in good yield (up to 80%). The diastereoselectivity of the reaction varied from 2:1 to 29:1 (syn:anti ) for 1a depending on reaction conditions. In the case of the Ireland-Claisen variant, the relationship between size of the alkyl groups on the enolate trap (Me 2 R%SiCl, R =Me, t-Bu, Ph) and diastereoselectivity was investigated, showing that chlorotrimethylsilane gave the best results. The size of the alkyl groups on the allylsilane do not exert a significant effect on the diastereoselectivity or yield (Me 2 RSi, R =Me, t-Bu, Ph, i-Pr).