A new soluble polymer-supported sulfonyl linker -: Application to the synthesis of cyclic α-amino acids

A new soluble poly(ethylene glycol)-supported protecting group of the SES (silylethylsulfonyl) type has been prepared and utilized in the synthesis of cyclic amino esters by ring-closing metathesis (RCM). Acidic cleavage from the support was performed to recover the fully deprotected amino acids. More conventional deprotection conditions with fluoride anions resulted in aromatization of the heterocycles in the case of the 6-membered ring and provided a new route to the synthesis of substituted pyridines. (C) Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002.