88224-11-7Relevant articles and documents
Allyl Esters as Selectively Removable Carboxy-protecting Functions in Peptide and N-Glycopeptide Syntheses
Waldmann, Herbert,Kunz, Horst
, p. 1712 - 1725 (2007/10/02)
Allyl esters are advantageous in protection of the carboxylic function in peptide and glycopeptide syntheses and can easily be synthesized from amino acids.They are stable under acidic conditions used for the removal of the Boc and Z groups.Under neutral or weakly basic conditions allyl esters are cleaved smoothly on treatment with catalytic amounts of tris(triphenylphosphane)rhodium(I) chloride in ethanol/water (9:1) leaving the N-protecting function and the N-glycosidic bond untouched.Selective deblocking of the α-carboxylic function of protected N-glycosylated asparagine derivatives 15 carried out in this way is exploited in C-terminal chain extension in the synthesis of N-glycotripeptides 17,e.g 17c, the latter representing a partial sequence of a human immunoglobulin G1.