Fluorenylmethoxycarbonyl group

FIGURE 3.11 Removal of the 9-fluorenylmethoxycarbonyl group by fcefa-elimination (Carpino Han, 1970). Deprotonation is achieved by hydroxide anion that generates dibenzofulvene or by piperidine that subsequently forms an addition product with the liberated moiety. 

Scheme 15 Synthesis of Tyrosine 0-Sulfate Peptides with the 9-Fluorenylmethoxycarbonyl Group for Temporary N"-Protection 421...

The 9-fluorenylmethoxycarbonyl group, developed by Carpino and co-workers in 1972 [257], has become one of the most widely used protective groups for aliphatic or aromatic amines in solid-phase synthesis. For solid-phase peptide synthesis in particular, this protective group plays an important role [258] (Section 16.1). The Fmoc group is not well suited for liquid-phase synthesis because non-volatile side products are formed during deprotection. 

The 9-fluorenylmethoxycarbonyl group is another distinguished contribution from the Carpino laboratory198199 to the solution-phase synthesis of peptides and latterly it has been adapted to solid-phase peptide synthesis too.200 The Fmoc group is exceptionally stable towards acid thus, carboxylic acids can be converted to acid chlorides with thionyl chloride201 or terf-butyl esters using sulfuric acid and isobutene.202 Furthermore, Fmoc groups are unscathed by HBr in... 

Fluorenylmethoxycarbonyl group) Deprotection (removal of Fmoc group)... 

The 9-fluorenylmethoxycarbonyl group provides a mode of protection to amines which is stable to acids and catalytic reduction cleavage (Scheme 124) is readily achieved under mild basic, non-hydrolytic conditions, a... 

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