Photocatalyzed Carbon−Carbon Bond Formation Between Glycerol and Electron‐Deficient Olefins

Abstract

Glycerol is produced in large quantities as a co‐product in the manufacturing of biodiesel and has received relatively little attention as a substrate for carbon‐carbon bond‐forming reactions. In this work, the photocatalyzed reaction between glycerol and electron‐deficient olefins is investigated to regioselectively insert an alkyl group at C2 in the triol. The results show that the transformation is highly dependent on the nature of the photocatalyst and the olefin. In the presence of an iridium catalyst and quinuclidine, glycerol can be coupled at C2 with sterically unhindered acrylates. In the presence of tetrabutylammonium decatungstate, glycerol can be reacted with fumaronitrile, N‐methyl maleimide, methyl acrylate and itaconic anhydride where the latter two substrates require the additional presence of potassium persulfate as an oxidant. These findings give rise to several new carbon‐carbon bond‐forming reactions with glycerol that allow the triol to be converted into more elaborate structures.

Decatungstate‐Catalyzed Carbon‐Carbon Bond Formation Between Furfural and Electron‐Deficient Olefins

“…It was therefore decided to perform the reaction for 24 hours. Changing the loading of TBADT to 2 % or 10 % gave in both cases rather low yields (entry 10 and 11) and the same was observed when the temperature was increased (entries [12][13][14]. Attempts to use boric acid and potassium persulfate [14] as additives to further promote the coupling were unsuccessful and only led to slightly diminished yields (entry 15 and 16).…”

“…Changing the loading of TBADT to 2 % or 10 % gave in both cases rather low yields (entry 10 and 11) and the same was observed when the temperature was increased (entries 12–14). Attempts to use boric acid and potassium persulfate [14] as additives to further promote the coupling were unsuccessful and only led to slightly diminished yields (entry 15 and 16). Exchanging the light source to a more powerful lamp did not influence the outcome if external cooling was ensured (entry 17).…”

“…Very recently, we have explored the photocatalyzed coupling between another platform molecule, i. e. glycerol, and electrondeficient olefins where the use of TBADT as the catalyst gave rise to the broadest substrate scope. [14] Herein, we describe a detailed investigation of the TBADTcatalyzed coupling between furfural and electron-deficient olefins. The carbon-carbon bond-forming reaction allows for the platform molecule to be transformed into a number of different furanyl ketones, which in many cases are new structures that have not been prepared before.…”

“…In addition, furfural has been reacted with acrylonitrile, ethyl acrylate and benzoquinone in the presence of other photocatalysts, [13] but besides these few examples, no systematic investigation has been performed on the photocatalyzed coupling between furfural and electron‐poor olefins. Very recently, we have explored the photocatalyzed coupling between another platform molecule, i. e. glycerol, and electron‐deficient olefins where the use of TBADT as the catalyst gave rise to the broadest substrate scope [14] …”