A visible-light-mediated tandem sulfonylation/cyclization of vinyl azides with sulfonyl hydrazines was developed that provides an efficient and simple strategy for the synthesis of valuable 6-(sulfonylmethyl)phenanthridines with a broad substrate scope and satisfactory yields under mild conditions.

No abstract

An efficient and facile visible-light-mediated tandem difluoromethylation/cyclization of alkenyl aldehydes, with easily accessible and air-stable [Ph3PCF2H]+Br– as the difluoromethylation reagent, has been established. A range of CF2H-substituted chroman-4-one skeletons and their derivatives, such as 2,3-dihydroquinolin-4­(1H)-ones, chroman, 3,4-dihydronaphthalen-1­(2H)-one, 2,3-dihydrobenzofuran, and 2,3-dihydro-1H-inden-1-one, are efficiently produced in moderate to good yields with excellent chemoselectivity under mild reaction conditions.

An efficient and facile strategy for the synthesis of 6‐(sulfonylmethyl)phenanthridines and its derivatives has been developed via tandem sulfonylation cyclization of vinyl azides under mild conditions in the absence of any catalysts and additives. The reaction simply utilizes easily accessible and cheap K2S2O5 as the sulfur dioxide source, delivering functionalized phenanthridines in moderate to excellent yields with operational simplicity and gram‐scale synthesis, as well as good functional‐group tolerance.

A class of the 9,9-dioctylfluorene-alt-5,7-bis(thiophen-2-yl)-2,3-biphenylthieno [3,4-b]pyrazine copolymeric derivatives (PFO-3ThPz-D) attaching additional donor (D) units in the pendant phenyl ring with a D-A D structure was synthesized and investigated, where the additional D unit is a substituent group of fluorene, carbazole, and triphenylamine (Tpa). Their photovoltaic properties were significantly tuned by these pending donor units. Among these copolymers, the PFO-3ThPz-Tpa exhibited the best photovoltaic properties in the bulk heterojunction polymeric solar cells (BHJ-PSC). The maximum power conversion efficiency (PCE) of 2.09% and the highest circuit current density (J sc ) of 7.91 mA/cm 2 were obtained in the cell using a blend of PFO-3ThPz-Tpa and PC 60 BM (1:3, w/w) as active layer, which are 2.5 and 1.8 times higher than those corresponding levels in the other cell using the parent PFO-3ThPz-Ph copolymer instead of PFO-3ThPz-Tpa as donor, respectively. While PC 60 BM was replaced by PC 70 BM, the PFO-3ThPz-Tpa-based BHJ-PSC exhibited better photovoltaic properties with PCE of 3.08% and J sc of 10.3 mA/cm 2 . This work demonstrated that attaching donor units into the D-A-based copolymeric side-chain is a simple and effective method to improve the photovoltaic properties for the resulting copolymers. V C 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 50: [4686][4687][4688][4689][4690][4691][4692][4693][4694] 2012