Photocatalytic C-C Bond Cleavage and Fluorosulfonylation of Strained Cycloalkanols for Carbonyl-Containing Aliphatic Sulfonyl Fluorides.

In this report, we present a photocatalytic ring-opening fluorosulfonylation of strained cycloalkanols with sulfur dioxide and NFSI under mild conditions for the synthesis of carbonyl-containing aliphatic sulfonyl fluorides. The synthetic potential of the carbonyl-containing aliphatic sulfonyl fluoride products has been examined by diverse transformations, including SuFEx reactions and Baeyer-Villiger oxidation reactions. Mechanistic studies demonstrate that the reaction operates through a radical C-C bond cleavage/SO2 insertion/fluorination cascade process.

Copper-Catalyzed Aminosulfonylation of O-Homoallyl Benzimidates with Sodium Sulfinates to Access Sulfonylated 1,3-Oxazines.

A facile copper-catalyzed aminosulfonylation of O-homoallyl benzimidates with sodium sulfinates in the presence of tert-butyl peroxybenzoate (TBPB) and XPhos ligand has been developed. By using this protocol, a variety of potentially bioactive 1,3-oxazines were directly synthesized. This method has the merits of a cheap catalyst, easily available and stable sulfone reagents, and simple operation.

[Biodegradation of Polystyrene by Geobacillus stearothermophilus].

Biodegradation is the most sustainable treatment method for waste polystyrene (PS). Thermophiles possess highly efficient biotransformation capabilities that could enhance the biodegradation efficiency of organic solid wastes. However, detailed research on the degradation of PS plastics by thermophile is scarce. Here, the degradation performance of a strain of Geobacillus stearothermophilus FAFU011 (FAFUA011) isolated from compost was examined. The results showed that strain FAFUA011 could utilize PS as the sole carbon source for growth and formed a stable biofilm on the surface of PS fragments. During 56 days of degradation, FAFU0011 caused a total mass loss of PS of 4.2% and decrease in molecular weight of 17.4%-18.2%. Based on SEM observations, FAFUA011 causes erosion hollows on the surface of PS, thus increasing the type and number of oxygen-containing structures that alter its hydrophilic properties. These changes facilitate the colonization of other microorganisms and further promote biodegradation. Based on 2D-COS analysis, the chronological order of the change in functional groups during the degradation process were identified as follows:1491 cm-1(C-H) > 1450 cm-1(C-H) > 1601 cm-1(C=C) > 1027 cm-1(C-O) > 1068 cm-1(C=O) > 1366 cm-1(C-OH). Overall, these results reveal that FAFU011 could promote the thermophilic bio-oxidative degradation of PS plastic.

Asymmetric synthesis of dihydrocoumarins via catalytic sequential 1,6-addition/transesterification of α-isocyanoacetates with para-quinone methides.

A catalytic asymmetric synthesis of 3,4-dihydrocoumarins with adjacent tertiary-quaternary stereocenters by 1,6-addition/transesterification cascade reaction of α-isocyanoacetates with ortho-hydroxyphenyl-substituted para-quinone methides (p-QMs) has been developed. Using a combination of dihydroquinidine-derived aminophosphine and silver nitrate as a binary catalytic system, moderate to good yields, excellent diastereoselectivities (>20 : 1 dr) and good to excellent enantioselectivities (up to 94% ee) were achieved for a wide range of isocyanoacetates and p-QMs.

Cinchona Alkaloid Squaramide-Catalyzed Asymmetric Ugi-Type Reaction of Isocyanoacetates with C,N-Cyclic Azomethine Imines: Access to Chiral Oxazole-Substituted Tetrahydroisoquinolines.

We reported herein an unexpected cinchona alkaloid-derived squaramide-catalyzed asymmetric two-component Ugi-type reaction of α-aryl-substituted isocyanoacetates with C,N-cyclic azomethine imines, which provides concise access to optically active C1-oxazole-substituted tetrahydroisoquinolines in good yields (86-93%) and high enantioselectivities (up to 98% enantiomeric excess) under mild conditions.