Oxidative α-C–C Bond Cleavage of 2° and 3° Alcohols to Aromatic Acids with O₂at Room Temperature via Iron Photocatalysis

Abstract

The selective α-C−C bond cleavage of unfunctionalized secondary (2°) and tertiary alcohols (3°) is essential for valorization of macromolecules and biopolymers. We developed a blue-light-driven iron catalysis for aerobic oxidation of 2°and 3°alcohols to acids via α-C−C bond cleavages at room temperature. The first example of oxygenation of the simple tertiary alcohols was reported. The iron catalyst and blue light play critical roles to enable the formation of highly reactive O radicals from alcohols and the consequent two α-C−C bond cleavages.Letter pubs.acs.org/OrgLett

Selective Degradation of Styrene‐Related Plastics Catalyzed by Iron under Visible Light**

“…From the reaction condition studies and the UV/Vis spectra (Figure 4c and Figure S9), Fe III is believed to be the real photocatalyst, which can be oxidized from Fe II simply under oxygen atmosphere. Based on the above observations and the relevant mechanism studies reported, [28,43,51,[54][55][56][57][58] the proposed Table 3. Depolymerization of different polymers through oxidative CÀ C bond cleavage.…”

“…[24][25][26][27][28][29][30][31][32][33] In addition, CÀ C bond scission of alcohols and ketones through alkoxyl radical intermediates applying inexpensive catalysts were reported recently. [34][35][36][37][38][39][40][41][42][43] Despite limitations, these results illustrate the possibility of developing an economic system for oxidative CÀ C bond cleavage in an environmentally friendly way (Figure 1b). Specially, iron may be a good catalyst candidate, which can perform both CÀ H bond oxidation [25,26,28] and oxidative CÀ C bond cleavage [43] through photocatalysis.…”

“…[34][35][36][37][38][39][40][41][42][43] Despite limitations, these results illustrate the possibility of developing an economic system for oxidative CÀ C bond cleavage in an environmentally friendly way (Figure 1b). Specially, iron may be a good catalyst candidate, which can perform both CÀ H bond oxidation [25,26,28] and oxidative CÀ C bond cleavage [43] through photocatalysis. [44][45][46][47][48][49] Iron halides, especially FeCl 3 , were found to catalyze the photo-oxidation of sp 3 CÀ H bonds of alkanes and arylalkanes with oxygen.…”

“…[28] FeCl 3 was also found by Zeng and co-workers to catalyze the photo-oxidative CÀ C cleavage of benzyl alcohols. [43] Illustrated by the two kinds of transformations, we proposed that a one-pot procedure may be realized for multiple CÀ H bond oxidation and CÀ C bond cleavage, which can be applied for the degradation of plastics (Figure 1c). Herein, we report an unprecedented procedure for styrene-related plastic depolymerization through multiple sp 3 CÀ H bond oxidation and oxidative cleavage of sp 3 CÀ C bond, using iron as the catalyst under visible light in air/oxygen atmosphere.…”

Selective degradation of styrene-contained plastics catalyzed by iron under visible light

“…Earth abundant metals were found to transform alkanes to alcohols and ketones under oxygen atmosphere [24][25][26][27][28][29][30][31][32][33] . In addition, C-C bond scission of alcohols and ketones through alkoxyl radical intermediates applying inexpensive catalysts were reported recently [34][35][36][37][38][39][40][41][42][43] . Though with limitations, these results illustrate us the possibility of developing an economic system for oxidative C-C bond cleavage in an environmentally friendly way (Fig.…”