Versatile direct dehydrative approach for diaryliodonium(III) salts in fluoroalcohol media

We have found that the use of fluoroalcohol media greatly enhanced the efficiency and scope of the direct dehydrative condensation of arenes and hypervalent iodine(III) compounds; the present clean method has a broad range of applicability as well as unique selectivity in the aromatic substrates, and is highly efficient even in polymer functionalization.     

3+2] coupling of quinone monoacetals by combined acid-hydrogen bond donor

The expeditious and efficient [3+2] coupling approach of quinone monoacetals 1 with alkene nucleophiles 2 by the action of an activated Br?nsted acid in the presence of a hydrogen bond donor perfluorinated alcohol has been achieved. With the optimized combined acid, the reaction could proceed under mild conditions by only mixing the two reactants to afford the cycloadducts 3 in a short time (within 10 min) with good to quantitative yields.     

Enhanced performance of photorefractive poly(N‐vinyl carbazole) composites

We present the enhanced photorefractive performance of high molecular weight poly(N‐vinyl carbazole) (PVCz)‐based composites. Higher diffraction efficiency with faster speed of grating build‐up was obtained by optimizing the composition of the PVCz composites. At relatively low applied electric field of E = 45 V μm^?1, diffraction efficiency of 26% for p‐polarized probe beam and corresponding that of 5.1% for s‐polarized probe beam were measured with faster grating build‐up speed of 48.3 s^?1 for the composite with 2,4,7‐trinitrofluorenone (TNF) as a sensitizer. Fastest speed of grating build‐up of 100 s^?1 and large optical gain up to 110 cm^?1 were measured at E = 80 V μm^?1 for the composite with fullerene derivative of PCBM as a sensitizer. These improved performances are due to a large orientational enhancement effect with faster response speed in addition to Pockels effect for the samples with appropriate glass transition temperature. © 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2011     

Clean and efficient benzylic C-H oxidation in water using a hypervalent iodine reagent: activation of polymeric iodosobenzene with KBr in the presence of montmorillonite-K10

We have found that unreactive and insoluble polymeric iodosobenzene [PhIO] n induced aqueous benzylic C-H oxidation to effectively give arylketones, in the presence of KBr and montmorillonite-K10 (M-K10) clay. Water-soluble and reactive species 1 having the unique I(III)-Br bond, in situ generated from [PhIO]n and KBr, was considered to be the key radical initiator during the reactions.     

Practical one-pot preparation of ketones from aryl and alkyl bromides with aldehydes and DIH via Grignard reagents

Various diaryl ketones, alkyl aryl ketones, and dialkyl ketones were efficiently prepared in good yields by the reactions of the Grignard reagents derived from aryl or alkyl bromides, followed by the reactions with aromatic or aliphatic aldehydes and the subsequent treatment with 1,3-diiodo-5,5-dimethylhydantoin and K₂CO₃, in a one-pot method. The same treatment of aromatic bromides bearing electron-withdrawing groups, such as ester, nitrile, ketone, and nitro groups with i-PrMgCl·LiCl or PhMgCl instead of Mg, also provided the corresponding diaryl and alkyl aryl ketones in good yields. The above methods are simple and practical transition-metal-free methods for the preparation of various diaryl ketones and alkyl aryl ketones bearing electron-rich aromatic groups and electron-deficient aromatic groups, as well as dialkyl ketones.     

A facile and clean direct cyanation of heteroaromatic compounds using a recyclable hypervalent iodine(III) reagent

The facile and clean direct cyanating reaction of pyrroles and thiophenes has been achieved using a recyclable hypervalent iodine(III) reagent 1b by a simple solid-liquid separation of the products and the reagent.