From trifluoroborates to acylboronates: cancer imaging as an incentive for the development of boron chemistry.
The past decade has seen the emergence of organotrifluoroborates as a useful class of substrates to perform various types of chemical reactions, including metal-mediated and/or photoredox cross-couplings. The Perrin group has also extensively studied their use in Isotopic Exchange with [18F]-fluorine for the direct radiolabeling of peptides and the one-step synthesis of PET (positron emission tomography) radiotracers for cancer imaging. More recently, this research led to the design of a new series of compounds targeting the prostate-specific membrane antigen (PSMA), reaching extremely high tumor/non-tumor contrast ratios for PET imaging of prostate cancer.
Considering unmet needs in imaging, we sought new methodologies to create original compositions with boronates. One new and attractive constellation of atoms comprising boron is the acylboronate. To date, the synthesis of this elusive motif has required several steps that necessarily include the use of highly basic anions. Starting from widely available vinylboronates, we have elucidated new synthetic methodologies that expand access to a variety of hydroxy- and acylboronates that will, in turn, be evaluated as radioprosthetics and/or bioisosteres.