Biocontrol potential of Cladosporium sphaerospermum against the wheat powdery mildew fungus Blumeria graminis f. sp. tritici.

Cladosporium spp. are known to be mycoparasites and inhibit phytopathogenic fungi. However, so far, little information is available on the impacts of Cladosporium spp. on powdery mildews. Based on the morphological characteristics and molecular analysis, C. sphaerospermum was identified as a mycoparasite on the wheat powdery mildew fungus (Blumeria graminis f. sp. tritici, Bgt, recently named as B. graminis s. str.). C. sphaerospermum was capable of preventing colony formation and conidial distribution of Bgt. The biomasses of Bgt notably decreased by 1.3, 2.2, 3.6 and 3.8 times at 2 dpi, 4 dpi, 6 dpi and 8 dpi, respectively. In addition, biomasses of C. sphaerospermum at 2 dpi, 4 dpi, 6 dpi and 8 dpi significantly increased to 5.6, 13.9, 18.2 and 67.3 times, respectively. In vitro, C. sphaerospermum exudates significantly impaired appressorial formation of Bgt. Thus, C. sphaerospermum acts as a potential biological control agent by suppressing the formation, distribution and development of Bgt conidia and is a viable alternative for managing the wheat powdery mildew. These results suggest that C. sphaerospermum is an antagonistic parasite of the wheat powdery mildew fungus, and hence, provide new knowledge about the biological control of phytopathogenic fungi.

Aliphatic Sulfonyl Fluoride Synthesis via Decarboxylative Fluorosulfonylation of Hypervalent Iodine(III) Carboxylates.

We disclose herein a photocatalytic decarboxylative fluorosulfonylation reaction of various hypervalent iodine(III) carboxylates in combination with 1,4-diazabicyclo[2.2.2]octane-bis(sulfur dioxide) adduct as a sulfonyl source and KHF2 as a desirable fluorine source via a radical sulfur dioxide insertion and fluorination strategy. A one-pot photocatalytic decarboxylative fluorosulfonylation reaction of various carboxylic acids mediated by PhI(OAc)2 was realized, as well. Notably, this transformation can be performed under heating conditions without the need for catalysts.

Aryl sulfonyl fluoride synthesis via organophotocatalytic fluorosulfonylation of diaryliodonium salts.

A mild and efficient synthesis of various aryl sulfonyl fluorides from diaryliodonium salts under organophotocatalysis via a radical sulfur dioxide insertion and fluorination strategy is presented. Diaryliodonium salts are used as aryl radical precursors, the 1,4-diazabicyclo[2.2.2]octane bis(sulfur dioxide) adduct (DABSO) as a sulfonyl source and cheap KHF2 as a desirable fluorine source, respectively. Notably, the electronic properties of substituents on the aromatic rings in diaryliodonium salts have a significant influence on the reaction yields.

Aryl sulfonyl fluoride synthesis via palladium-catalyzed fluorosulfonylation of aryl thianthrenium salts.

We developed an efficient palladium-catalyzed fluorosulfonylation reaction of aryl thianthrenium salts to smoothly prepare various aryl sulfonyl fluorides using cheap Na2S2O4 as a convenient sulfonyl source in combination with N-fluorobenzenesulfonimide (NFSI) as an ideal fluorine source under mild reduction conditions. A one-pot synthesis of aryl sulfonyl fluorides starting from various arenes was established as well without the need for separating aryl thianthrenium salts. The practicality of this protocol was demonstrated by gram-scale synthesis, derivatization reactions, and excellent yields.