METHOD FOR TEMPORARY PROTECTION OF CARBOXYL GROUPS BY ESTERIFICATION WITH -SILYL-ETHYL ALCOHOLS AND CERTAIN NOVEL AMINOACID ESTERS OF THIS TYPE

摘要

The esterification of carboxylic acids with .beta.-silyl-ethyl alcohols of the formula ¢(I)-OH!, in which each of R1, R2 and R3 independently represents a hydrocarbon radical and the individual radicals can be linked a single C-C bond,gives corresponding novel esters, the .beta.silylethyl ester group of which can be split off, with liberation of the carboxyl group, by treatment with a salt of hydrofluoric acid, especially a fluoride of a quaternary organic base. Sincc these conditions are very mild and specific, ester groups of this type are suitable as carboxyl protective groups, especially in polyfunctional compounds, such as steroids, prostaglandines, .beta.-lactam compounds and, above all, aminoacids and peptides, in which the other functional groups, including other carboxyl groups, can be protected in a conventional manner.