3,5-Bis(perfluorodecyl)phenylboronic acid has been synthesized based on the direct coupling of perfluorodecyl iodide with 1,3-diiodobenzene. This new boronic acid is shown to be a "green" catalyst for the direct amide condensation reaction by virtue of the strong electron-withdrawing effect and the immobility in the fluorous recyclable phase of the perfluorodecyl group.Arylboronic acids bearing electron-withdrawing substituents at the aryl group behave as water-, acid-, and basetolerant thermally stable Lewis acids and can be easily handled in air. We have succeeded in enhancing the catalytic activities of a chiral acyloxyborane (CAB) derived from 2,6-di(isopropoxy)benzoyltartaric acid and borane×THF, Corey's chiral oxazaborolidine catalyst derived from N-(p-toluenesulfonyl)-(S)-tryptophan and borane×THF, and the Brønsted acid-assisted chiral Lewis acid (BLA) derived from chiral tetrol and borane×THF by a modified method using 3,5-bis(trifluoromethyl)phenylboronic acid (1) instead of borane•THF. 1−3 Moreover, we have found that 1 and 3,4,5-trifluorophenylboronic acid (2) are highly effective catalysts for the amide condensation of amines (1 equiv) and carboxylic acids (1 equiv). 4 To the best of our knowledge, this is the first example of a catalytic and direct amide condensation which does not require excess amounts of substrates.Most of the above homogeneous catalytic reactions require relatively large quantities of arylboronic acid catalysts (1~20 mol%), and trace amounts of the catalysts must be removed from the reaction products. This has hampered the application of this methodology to largescale syntheses. Recently, the concept of fluorous bi-phasic catalysis (FBC) was introduced as an environmentally benign recycling process. 5−7 In this paper, we describe a convenient and high-yielding route to phenylboronic acids 3 and 4 bearing perfluorinated ponytails based on the direct coupling of fluoroalkyl iodides with halobenzenes and their catalytic and recyclable application in a direct amide condensation.Cross-coupling of fluoroalkyl iodides with iodoaromatic compounds to give fluoroalkyl-substituted aromatics in the presence of copper was reported by McLoughlin and Thrower more than three decades ago. 8 Prompted by this early finding, we attempted the synthesis of perfluoroalkylated phenylboronic acids 3 and 4 (Scheme). Treatment of 4-iodoanisole (5) and perfluorodecyl iodide in DMSO (120°C, 40 h) gave the substituted anisole 6 in 90% yield. 9 Compound 6 was converted to 7 by demethylation with boron tribromide (70% yield) and subsequent triflation with triflic anhydride (>99% yield). The palladium-catalyzed cross-coupling of triflate 7 with bis(pinacolato)diboron yielded the corresponding arylboronate 8 in 81% yield. 10a Finally, 8 was converted to 3 11 in 70% yield by treatment with boron tribromide. Thus, the new boronic acid 3 was prepared from 5 in five steps. In a similar manner, 3,5-bis(perfluorodecyl)phenylboronic acid (4) 12 was prepared from 1,3-diiodobenzene (9) in four steps: copper-mediated cou...

Keep it simple: A titanium complex with a salan ligand bearing phenyl groups at C3 and C3′ is an efficient catalyst for the enantioselective epoxidation of unfunctionalized olefins with aqueous hydrogen peroxide (see scheme); furthermore, the epoxidation was stereospecific. The C3 and C3′ substituents stabilize this complex and enhance the asymmetric induction.

A robust hydrogel with a reliable deformation region in an aqueous environment is proposed. The gel has a homogeneous network where hydrophilic/hydrophobic components are uniformly distributed. In an aqueous environment, aggregated hydrophobic segments serve as "mechanical fuse links," inhibiting sudden macroscopic fracture. The gel endures threefold stretching for more than 100 cycles in water without mechanical hysteresis.

Structural analysis of inhomogeneity-free poly(ethylene glycol)− poly(dimethylsiloxane) (PEG−PDMS) amphiphilic conetwork gels has been performed by the complementary use of small-angle X-ray and neutron scattering. Because of the hydrophobicity of PDMS units, the PEG−PDMS gels exhibit a microphase-separated structure in water. Depending on the volume fraction of PDMS, the microphase-separated structure varies from core−shell to lamellar. The obtained X-ray and neutron scattering profiles are reproduced well using a core− shell model together with a Percus−Yevick structure factor when the volume fraction of PDMS is small. The domain size is much larger than the size of individual PEG and PDMS unit, and this is explained using the theory of block copolymers. Reflecting the homogeneous dispersion conditions in the as-prepared state, scattering peaks are observed even at a very low PDMS volume fraction (0.2%). When the volume fraction of PDMS is large, the microphase-separated structure is lamellar and is demonstrated to be kinetically controlled by nonequilibrium and topological effects.