Functional Graphenic Materials Via a Johnson−Claisen Rearrangement

Abstract

Current research in materials has devoted much attention to graphene, with a considerable amount of the chemical manipulation going through the oxidized state of the material, known as graphene oxide (GO). In this report, the hydroxyl functionalities in GO, the vast majority that must be allylic alcohols, are subjected to Johnson-Claisen rearrangement conditions. In these conditions, a [3,3] sigmatropic rearrangement after reaction with triethyl orthoacetate gives rise to an ester functional group, attached to the graphitic framework via a robust C-C bond. This variation of the Claisen rearrangement offers an unprecedented versatility of further functionalizations, while maintaining the desirable properties of unfunctionalized graphene. The resultant functional groups were found to withstand reductive treatments for the deoxygenation of graphene sheets and a resumption of electronic conductivity is observed.The ester groups are easily saponified to carboxylic acids in situ with basic conditions, to give water-soluble graphene. The ester functionality can be further reacted as is, or the carboxylic acid can easily be converted to the more reactive acid chloride. Subsequent amide formation yields up to 1 amide in 15 graphene carbons and increases intergallery spacing up to 12.8 Å, suggesting utility of this material in capacitors and in gas storage. Other functionalization Submitted to 22222222224222 schemes, which include the installation of terminal alkynes and dipolar cycloadditions, allow for the synthesis of a highly positively charged, water-soluble graphene. The highly negatively and positively charged graphenes (zeta potentials of -75 mV and +56 mV, respectively), have been successfully used to build layer-by-layer (LBL) constructs.

Layer-by-layer Nanoarchitectonics: Invention, Innovation, and Evolution

“…275 Hydroxy functionalities in GO can be subjected to JohnsonClaisen rearrangement and sigmatropic rearrangement after reaction with triethyl orthoacetate to give ester functional groups. The ester groups are easily saponified to carboxylic acids that can be also used for introduction of various functional groups.…”

Green Processing of Carbon Nanomaterials

“…After this reaction, a similar turnover rate was obtained after further addition of the substrate, suggesting that a lack of product inhibition was observed under the conditions. [77] Copyright 2013, WILEY-VCH. [75] The surface reaction of the membrane occurred through EDC and NHS coupling to yield amine-reactive esters in 2-(N-morpholino)ethanesulfonic acid (MES) buffer.…”

“…[77] The unsaturated ester occurs in the presence of allylic alcohol and orthoesters such as triethyl orthoacetate (TEOA) with a catalytic amount of acid ( Figure 6c). [77] The unsaturated ester occurs in the presence of allylic alcohol and orthoesters such as triethyl orthoacetate (TEOA) with a catalytic amount of acid ( Figure 6c).…”

The Orthoester Johnson–Claisen Rearrangement in the Synthesis of Bioactive Molecules, Natural Products, and Synthetic Intermediates – Recent Advances

“…The syntheses of xylobovide (204), [112] canadensolide (205), [113] sporothriolide (206), [114] and nor-canadensolide (207) by the preceding strategy were achieved by the Fernandes group. On the other hand, as shown in Scheme 40, the synthesis of the other two isomers of phenatic acid B (ent-190a and ent-190b) was accomplished from the chiral diol ent-191.…”

“…On the other hand, as shown in Scheme 40, the synthesis of the other two isomers of phenatic acid B (ent-190a and ent-190b) was accomplished from the chiral diol ent-191. Lactones 201b and 203b were used for the synthesis of xylobovide (204) and sporothriolide (206), respectively. The syntheses of xylobovide (204), [112] canadensolide (205), [113] sporothriolide (206), [114] and nor-canadensolide (207) by the preceding strategy were achieved by the Fernandes group.…”