Site-specific modification of proteins with functional molecules provides powerful tools for researching and engineering proteins. Here we report a new chemical conjugation method which photocages highly reactive but chemically selective moieties, enabling the use of protein-inert amines for selective protein modification. New amino acids FnbY and FmnbY, bearing photocaged quinone methides (QMs), were genetically incorporated into proteins. Upon light activation, they generated highly reactive QM, which rapidly reacted with amine derivatives. This method features a rare combination of desired properties including fast kinetics, small and stable linkage, compatibility with low temperature, photocontrollability, and widely available reagents. Moreover, labeling via FnbY occurs on the β-carbon, affording the shortest linkage to protein backbone which is essential for advanced studies involving orientation and distance. We installed various functionalities onto proteins and attached a spin label as close as possible to the protein backbone, achieving high resolution in double electron−electron paramagnetic resonance distance measurements.
Amines Q 0120Stereoselective Nucleophilic Monofluoromethylation of N-(tert-Butanesulfinyl)imines with Fluoromethyl Phenyl Sulfone. -A highly stereoselective nucleophilic monofluoromethylation of chiral sulfinylimines with fluoromethyl phenyl sulfone is developed. The products are obtained in excellent yield with high stereoselectivity (99:1 or 98:2). Without purification, they are converted into α-monofluoromethylamine salts (VI) via reductive desulfonation and removal of the tert-butanesulfinyl group. The same methodology is also used to synthesize homochiral α-monofluoromethylated cyclic secondary amines using tosylate-bearing (R)-(tert-butanesulfinyl)imine precursors (VII). -(LI, Y.; NI, C.; LIU, J.; ZHANG, L.; ZHENG, J.; ZHU, L.; HU*,
Catalytic sustainable transformation of carbon dioxide into valuable fine chemicals with high efficiency is a global challenge even CO2 is an abundant, nontoxic, and sustainable carbon feedstock but one of...
Hydrosilylation employing metal-organic frameworks (MOFs) as the catalyst are promising because of their high catalytic reactivity and sustainability of heterogeneous catalyst. A highly simple and efficient method for the hydrosilylation of olefins catalyzed by an air-stable MOF-cobalt catalysts is developed. This approach is featured by 0.1% of Co-MOFs catalyst with excellent reactivity, recyclability, and good functional group tolerance. The Co-MOFs can catalyze hydrosilylation of styrene or its derivatives with Ph 2 SiH 2 in the presence of NaBHEt 3 . Moreover, the catalysts we developed show excellent stability, and the activity is not significantly reduced after repeating the cycle for five times.
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