•A Fe2O3-catalyzed Pummerer rearrangement was explored.•Applications of the method led to a series of important alkylthiomethyl molecules.•The product structure was further confirmed by X-ray analysis of its single crystal.A simple, effective approach for the Pummerer rearrangement of acyl chlorides with sulfoxides by using a low-cost and more abundant Fe catalyst has been described. The alkylthiomethyl ester products were prepared in good to excellent yields for a range of different substrates including asymmetrical sulfoxides and acyl chlorides with a variety of functional groups under mild reaction conditions. The reaction features short reaction time, simple manipulation, cheap reagents and a broad substrate scope. Single crystal X-ray analysis of a representative methylthiomethyl (MTM) group containing product was also reported.Download high-res image (49KB)Download full-size image

Although monodisperse polyethylene glycols (M-PEGs) above 4000 Da are especially valuable in biomedical applications, their synthesis remains a long-standing challenge. To this end, a peptide-based strategy for such M-PEGs was developed. With macrocyclic sulfates as the key intermediates, a panel of oligoethylene glycol (OEG) containing ω-amino acids were prepared with high efficiency. Through solid phase peptide synthesis (SPPS), these amino acids were conveniently assembled into a series of amide bond-containing M-PEGs with high flexibility in molecular weight and amide density selection. With this strategy, an M-PEG of 10262 Da was prepared on a gram scale and its biocompatibility was assessed in a mice model.

A highly practical copper-catalyzed intermolecular chloroazidation of α,β-unsaturated amides has been described, giving a series of azidochlorides in good-to-excellent yields. The stable azidoiodine(III) reagent and SOCl2 were used as azide and chlorine sources, respectively. The synthetic applications of this protocol were also explored by a variety of synthetically useful transformations.

We have developed a process for the efficient and scalable preparation of heterofunctionalized dodecaethylene glycol from the readily available tetraethylene glycol and its macrocyclic sulfate. By employing the benzyl group as both a protecting group and a separative tag, multiple chromatographic separations were avoided. With this method, α-amino-ω-methyl-dodecaethylene glycol was prepared on a 53 g scale with high purity and 61% overall yield in eight steps and one chromatographic separation.

Mono-dispersed poly(ethylene glycols) (PEGs) are of great value in the development of biopharmaceuticals. However, tedious synthesis limits the availability of mono-dispersed PEGs. To address this issue, a fluorous synthesis of mono-dispersed PEGs, discretely PEGylated surfactants and 19F magnetic resonance imaging (MRI) agents has been developed. During the synthesis, both fluorous and normal phase silica gel-based solid-phase extractions were successfully employed to simplify the purifications. This synthesis provided an easy access to valuable mono-dispersed PEGs and related molecules for biomedical application on multi-gram scales.

A highly practical copper-catalyzed intermolecular halotrifluoromethylation of alkenes has been developed under mild reaction conditions. A variety of Cl/Br-containing trifluoromethyl derivatives were directly synthesized from a wide range of alkenes, including electron-deficient and unactivated alkenes.

A highly practical copper-catalyzed intermolecular chloroazidation of α,β-unsaturated amides has been described, giving a series of azidochlorides in good-to-excellent yields. The stable azidoiodine(III) reagent and SOCl2 were used as azide and chlorine sources, respectively. The synthetic applications of this protocol were also explored by a variety of synthetically useful transformations.

Although monodisperse polyethylene glycols (M-PEGs) above 4000 Da are especially valuable in biomedical applications, their synthesis remains a long-standing challenge. To this end, a peptide-based strategy for such M-PEGs was developed. With macrocyclic sulfates as the key intermediates, a panel of oligoethylene glycol (OEG) containing ω-amino acids were prepared with high efficiency. Through solid phase peptide synthesis (SPPS), these amino acids were conveniently assembled into a series of amide bond-containing M-PEGs with high flexibility in molecular weight and amide density selection. With this strategy, an M-PEG of 10262 Da was prepared on a gram scale and its biocompatibility was assessed in a mice model.