Serine linkers based

HIT-linked peptides proved to be valuable tools to assess the a-helix induction potential of HIT-1. CD measurements revealed that HIT-1 has a high a-helix inducing potential at the N-terminus. Incorporated at internal positions, HIT-1 proved to be a moderate a-helix inducer and it strongly initiated the formation of 310-helical conformations once incorporated at the C-terminus. Based on these results, and for reasons of chemical stability, we replaced the (/ )-serine linker by the more rigid and a-helix compatible (/ )-a-methylserine analogue.203... 

Silyl-derived linker 36 was prepared in three steps from a silyl ether of serine and incorporated for Fmoc/tBu-based assembly of protected gly-copeptide blocks (Scheme 11) [42]. The a-carboxylic acid function of serine was protected as an allyl ester. Deprotection by a Pd(0) catalyst in the presence of dimedone liberated the carboxylic acid in order for subsequent... 

Chou Y-L, Morrissey MM, Mohan R. Novel serine-based linker for the solid-phase synthesis of organic compounds. Tetrahedron Lett 1998 39 757-760. 

Few examples have been described of nucleophilic cleavage of carbonate- or carbamate-linked alcohols from insoluble supports. A serine-based linker for phenols releases the phenol upon fluoride-induced intramolecular nucleophilic cleavage of an aryl carbamate (Entry 2, Table 3.36). A linker for oligonucleotides has been described, in which the carbohydrate is bound as a carbonate to resin-bound 2-(2-nitrophen-yl)ethanol, and which is cleaved by base-induced 3-elimination (Entry 3, Table 3.36). Trichloroethyl carbonates, which are susceptible to cleavage by reducing agents such as zinc or phosphines, have been successfully used to link aliphatic alcohols to silica gel (Entry 4, Table 3.36). These carbonates can also be cleaved by acidolysis (Table 3.22). 

---