29285-16-3

Emulating the function of natural carboxylases to convert CO2 under atmospheric condition is a great challenge. Herein we report a class of CO2-folded single-chain nanoparticles (SCNPs) that can function as recyclable, function-intensified carboxylase mimics. Lewis pair polymers containing bulky Lewis acidic and basic groups as the precursor, can bind CO2 to drive an intramolecular folding into SCNPs, in which CO2 as the folded nodes can form gas-bridged bonds. Such bridging linkages highly activate CO2, which endows the SCNPs with extraordinary catalytic ability that can not only catalyze CO2-insertion of C(sp3)-H for imitating the natural enzyme's function, it can also act on non-natural carboxylation pathways for C(sp2 and sp)-H substrates. The nanocatalysts are of highly catalytic efficiency and recyclability, and can work at room temperature and near ambient CO2 condition, inspiring a new approach to sustainable C1 utilization.

A facile and general synthesis of 2,2-dimethyl-1,3-dioxin-4-one derivatives (1) is reported.Treatment of β-keto acids with a mixture of isopropenyl acetate and conc. sulfuric acid gave 2,2-dimethyl-1,3-dioxin-4-ones (1).Similar treatment of tert-butyl esters of β-keto acids also gave 1.KEYWORDS - 2,2-dimethyl-1,3-dioxin-4-one derivative; diketene-acetone adduct; diketene; acylketene; β-keto acid; β-keto ester

Lithium 1,8-diazabicycloundec-7-en-6-ide (1) has underwent the insertion of carbon dioxide and the resulting lithium 6-carboxylato complex (2) transferred the carboxylato moiety to active methylene compounds (3) such as p-nitroacetophenone, acetophenone, p-methoxyacetophenone, and S-benzylthioacetate under mild conditions.

It is found that magnesium(II) N,N'-dicyclohexylamidinide complexes are useful reagents for the fixation of carbon dioxide and the transfer of the captured carbon dioxide moiety to active methylene compounds.