Scheme 4. Transition metal-based approaches for tyrosine modification. (a) An electrophilic π-allyl palladium complex for tyrosine O-alkylation. (b) A method relying on a cerium(iv) salt to generate tyrosyl radicals. (c) A ruthenium(ii) photocatalyst to generate tyrosyl radicals for subsequent modification. (d) Bioconjugation of tyrosine residues with an η6 Rh(iii) complex.
