The development of a multicatalytic one-pot synthesis of 2-arylbenzofurans starting from aryl halides and 2-halophenols is described. The protocol involves two Sonogashira coupling reactions, followed by 2-ethynylphenol cyclization leading to 2-arylbenzofuran derivatives. The process occurs smoothly under mild conditions, giving products in good yields, and can be applied to many 2-arylbenzofurans substituted both at 2-aryl position and in the benzodifuran moiety. Substituents such as halogens, hydroxyl, cyano, nitro, and amino groups are tolerated, enabling further functionalization of the system.

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The catalytic asymmetric reduction of a-keto aldoxime O-methyl, O-benzyl, and O-trityl ethers, derived from substituted acetophenones, with borane/oxazaborolidines, by transfer hydrogenation, and with yeast, was studied. The reduction with borane/oxazaborolidines produced the corresponding a-hydroxy oxime ethers, a-hydroxy hydroxylamine ethers, and b-amino alcohols in 39-78% yields and up to 77% ee. The carbonyl group was selectively reduced by transfer hydrogenation with formic acid-triethylamine catalyzed by RhCl[(R,R)-TsDPEN](C 5 Me 5), and also with yeast, producing a-hydroxy oxime ethers, up to 75% ee and 93% ee, respectively.

a b s t r a c tThe synthesis of 4,4 0 -dibenzodifuran-2,2 0 -bipyridine derivatives as ligands of organic ruthenium dyes for DSSC applications is described. Two new heteroleptic ruthenium complexes have been prepared and compared with commercially available N719 and Z907 dyes, using dip dyeing and flow dyeing methods in large area testing cells prepared for industrial purposes. The newly synthesized dyes revealed higher solar-to-electric energy conversion efficiency (h), measured at the AM1.5G conditions, up to 21% compared to N719 and up to 46% compared to Z907, and external quantum efficiency of 53%. These results can be explained by enhanced light-harvesting of the benzodifuran moiety of the dyes that is related to photocurrent.

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