Main observation and conclusion
While polystyrene is widely used in daily life as a synthetic plastic, the subsequently selective degradation is still very challenging and highly required. Herein, we disclose a highly practical and selective reaction for the catalytically efficient oxidation of alkyl aromatics (including 1°, 2°, and 3° alkyl aromatics) to carboxylic acids. While dioxygen was used as the sole terminal oxidant, this protocol was catalyzed by the inexpensive and readily available ferric compound (FeCl3) with irradiation of visible light (blue LEDs) under only 1 atmosphere of O2 at room temperature. This system could further facilitate the selective degradation of polystyrene to benzoic acid, providing an important and practical tool to generate high‐value chemical from abundant polystyrene wastes.
We report an alkoxy radical process
for the C–C bond cleavage
and functionalization of unstrained tertiary and secondary cyclic
alcohols. In the absence of a chlorine atom, the readily available
iron catalysts [Fe(OBu-t)3 or Fe(acac)3/t-BuONa] facilitate alkoxy radical formation
via the direct ligand-to-metal charge transfer of Fe alkoxide and
further enable the ring opening and amination of cyclic alcohols.
The remote amino carbonyl compounds could be obtained with a broad
scope in up to excellent yields under the mildly redox-neutral system.
Light-driven electron transfer, alkoxy radical formation, and subsequent
C–C bond cleavage via β-scission were the keys to the
transformation.
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
The efficient conversion of a C−H bond in the polyether chain to other functional groups provides great opportunities for development of novel applications in many research fields. However, this field is quite underdeveloped due to the key challenge on controlling the selectivity of the C−H bond functionalization over the chain cleavage. In this work, we report a controllable C−H bond alkylation of polyethers under mild conditions via photoinduced iron catalysis. The level of functionalization could be controlled by using different amounts of alkenes and various reaction times, while the molecular weight distributions were maintained narrow. A broad scope of electron-deficient alkenes containing nitrile, ester, epoxide, terminal alkynyl, 2,5-dioxotetrafuranyl, and 2,5-dioxopyrrolidinyl groups could be utilized to functionalize the different polyethers with great efficiencies. The potential applications of the modified polyethylene glycols and polyethylene oxides were explored by the preparation of novel hydrogels and solid-state electrolytes with enhancement of lithium ion conductivities. Moreover, the density functional theory calculation disclosed the plausible mechanism and explained the high selectivity for the C− H alkylation.
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