Our research group focuses on the use of hypervalent iodine (HVI) reagents as a method of organic synthesis. In our lab, we use HVI reagents to add halogens to molecules and produce cyclopropane systems.
Check out our current projects below to see what we are up to now.
Incorporation of radioactive fluorine (18F) in biologically relevant molecules
Radiofluorination is a technology at the centre of the development of imaging probes for positron-emitting tomography (PET). What sets apart hypervalent iodine-based reagents in fluorination is their ability to effectively transfer an "F+" synthon, therefore reversing the polarity of the fluoride (F-) obtained from standard cyclotron sources. In order to successfully conduct the project, Leanne focuses on the design of hypervalent iodine precursors which will both readily undergo ligand exchange with fluoride and allow for facile purification of the fluorinating agent before the reaction with the scaffold of interest (probe).
Production of cyclopropanes through monocarbonyl iodonium ylides
As iodonium ylides are only operative for methylenes flanked by two electron withdrawing substituents, we are trying to prepare monocarbonyl iodonium ylides (MCIYs), and explore their efficacy as metallocarbene precursors. MCIYs can be generated in situ from Wittig reagents, which then act as carbene precursors.
* WORK IN PROGRESS
See our Publications page for more of our past work.
New reactions of hypervalent iodine (HVI) reagents
In a-Carbonyl Functionalizations:
Functionalizing the a-carbonyl position with HVI reagents traditionally transfers either X1 or X2 to a substrate. We if the substrate already possessed a suitable leaving group:
Given how many types of differently-substituted hypervalent iodine reagents there are out there, this could be a highly effective way to do metal-free, double alpha-carbonyl bond formation in a single transformation. The reaction works quite well for transfer of chloride or fluoride, and we recently published our first set of results in JACS.
We are currently investigating the substrate scope of these transformations, expanding the methodology into indole-, chromane- and aliphatic-based diazocarbonyls. We are also investigating diaryliodoniun salts (or similar species) as aryl transfer reagents in this chemistry.
As Metallocarbene Precursors:
Metallocarbenes are versatile synthetic intermediates that can be accessed from iodonium and diazonium ylides.
As iodonium ylides are only operative for methylenes flanked by two electron withdrawing substituents, we are trying to prepare monocarbonyl iodonium ylides (MCIYs), and explore their efficacy as metallocarbene precursors:
MCIYs can be generated in situ from Wittig reagents, which then act as carbene precursors.
If you are interested in our research, or would like to learn more about what we do, feel free to contact Graham Murphy or stop by C2-367.