Photorelease of tyrosine from α-carboxy-6-nitroveratryl (αCNV) derivatives

The synthesis of photolabile tyrosine derivatives protected on the phenolic oxygen by the alpha-carboxy-6-nitroveratryl (alpha CNV) protecting group is described. The compounds undergo rapid photolysis at wavelengths longer than 300 nm to liberate the corresponding phenol in excellent yield (quantum yield for the deprotection of tyrosine = 0.19). Further protection of caged tyrosine is possible, yielding N-Fmoc protected derivatives suitable for direct incorporation of caged tyrosine in solid-phase peptide synthesis.