# Hydrophilic BIPHEPHOS Ligand for Pd-Mediated Cysteine Allylation of Peptides and Proteins in Water

## TL;DR

A new water-soluble ligand enables efficient modification of peptides and proteins under biocompatible conditions.

## Contribution

A hydrophilic BIPHEPHOS ligand with diethyl phosphonates is introduced for aqueous Pd-mediated cysteine allylation.

## Key findings

- The hydrophilic BIPHEPHOS ligand is catalytically isofunctional to unpolar tert-butyl.
- Native prenyl groups and bioconjugation handles were successfully introduced into peptides and proteins.
- The method works under nearly aqueous conditions, improving biocompatibility.

## Abstract

The selective and natural post-translational modification
of peptides
and proteins under biocompatible conditions remains a challenge. Herein,
we report a hydrophilic variant of the BIPHEPHOS ligand featuring
diethyl phosphonates as solubilizing groups, which were found to be
catalytically isofunctional to unpolar tert-butyl.
This enabled the fast introduction of native prenyl groups and bioconjugation
handles into peptides and folded proteins under nearly aqueous conditions.