N-Boc-α-tosylsarcosine ethyl ester: An α-amido sulfone for the regio- and stereoselective synthesis of protected γ,δ-unsaturated N-methyl-α-amino acids by palladium-catalyzed nucleophilic substitution

✍ Scribed by Diego A. Alonso; Ana Costa; Carmen Nájera

• Publisher: Elsevier Science
• Year: 1997
• Tongue: French
• Weight: 176 KB
• Volume: 38
• Category: Article
• ISSN: 0040-4039
• DOI: 10.1016/s0040-4039(97)10054-5

✦ Synopsis

N-Boc-u-msylsarcosine ethyl ester (3) reacts under neutral conditions either with allylic carbonates or with vinyloxinme in the presence of a catalytic amount of Pd(PPh3) 4 and dppe (5 mol%) to give regio-and stereoselectively the corresponding allylated products $ and 6, respectively. Reductive desulfonylation of these compounds with Mg-MeOH affords the corresponding protected 7,8-ansaturated N-methyl-cz-amino acids 7 and 8.