Bismuth Chemistry

Organobismuths synthesis

triarylbismuths synthesis.tiff

Bismuth occupies the 83rd position of the periodic table.

This element is not only the heaviest natural member

of the pnictogens but also the heaviest stable and

non-radioactive atom of the periodic table.

Contrary to its immediate neighbours such

as lead, tin, antimony, tellurium and polonium,

this element shows low toxicity, allowing

its use in therapeutic ingredients and

in the development of reactions that

are more respectful of the

environment

(green chemistry).

Organobismuth compounds

are organometallic species

that contain one or multiple

C–Bi bonds. These species

possess diversified properties that

are less commonly found with other

elements of the p block. They can exist

with the bismuth at +3 (trivalent) and

+5 (pentavalent) oxidation state, can

accommodate up to 6 ligands and

can be neutral, anionic, cationic or dicationic.

Our journey in the chemistry of bismuth started in 2007 with the publication of the first synthesis of tricyclopropylbismuth and its use in the first N-cyclopropylation reaction of amides, indoles and N–H-containing heterocycles. Since then, we reported the synthesis of a multitude of triaryl and triheteroarylbismuth compounds through the addition of Grignard reagents to bismuth trichloride. The X-ray crystal structure of many of these species showed 90° C–Bi–C angles and various stacking modes (head–to–head, head–to–tail, tail–to–tail, etc). We also demonstrated that the functional groups on the organobismuth compounds could be modified using acidic, basic, oxidative and organometallic conditions, giving access to organobismuth species bearing groups that are incompatible with the Grignard reagents. These species have then been used in various copper and palladium-catalyzed reactions that lead to the formation of C–C, C–N, C–O and C–S bonds. Over time, our group has established itself as a leader in the field of bismuth chemistry by publishing more than 20 communications on the topic, one review in Synthesis and another one in Science of Synthesis. Recently, due to our expertise in the field, we have been invited to comment on an article published in Nature Chemistry on the ortho-arylation of phenols using a universal bismuth reagent.

Our group is currently working to increase the diversity of organobismuth compounds that incorporate a wider range of functional groups. We are also working on expanding the use of these unique species in other reactions that can find applications in organic synthesis and medicinal chemistry. We are also working on the design of organobismuth compounds that possess non-transferable spectator ligands that stimulate the transfer of the aryl group while increasing the atom-economy of the processes. We are also actively working on the synthesis of organobismuth compounds that possess alkenyl, alkynyl, alkyl and cyclopropyl groups.

Functionalization organobismuth.tiff