Bsmoc group

The Bsmoc derivative is formed from the chloroformate or the A -hydroxy-succinimide ester. It is cleaved rapidly by a Michael addition with tris(2-aminoethyl)amine at a rate that leaves Fmoc derivatives intact. More hindered bases, such as A -methylcyclohexylamine or diisopropylamine, do not react with the Bsmoc group, but do cleave the Fmoc group, illustrating the importance of steric effects in additions to Michael acceptors. 

Reagent for Amino Group Protection. The Bsmoc group was recommended for protection of the a-amino function of amino acids. Such Bsmoc amino acids are useful substitutes for Fmoc amino acids for solid phase and especially rapid continuous solution syntheses of peptides. Deblocking by lower concentrations of piperidine than required for the Fmoc residue avoids base-induced side reactions. An example involves the assembly of pentapeptide 1. ... 

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