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OBJECTIVE We aimed to investigate whether Chinese endoscopists without narrow-band imaging (NBI) experiences could achieve high accuracy in the real-time diagnosis of colorectal polyps using NBI International Colorectal Endoscopic (NICE) classification after web-based training. METHODS Altogether 15 endoscopists from five centers with no NBI experiences followed a short, web-based training program on the NICE classification and took web-based test. Their performances were compared with 15 matched experienced endoscopists with no NBI experience who received no NBI training. These 15 trained endoscopists then made real-time diagnoses of colorectal neoplasia. A logistic regression was used to assess potential predictors of diagnostic performance. RESULTS Compared with those who received no training, trained endoscopists achieved comparable overall accuracy (85.3% vs 83.1%, P = 0.408) and accuracy at a high-confidence level (87.0% vs 86.0%, P = 0.670), but had a higher confidence rate (86.1% vs 83.7%, P = 0.004) for the diagnosis of neoplasia. Real-time diagnostic accuracy, sensitivity and specificity were 94.3% (95% confidence interval [CI] 91.5%-96.2%), 96.2% (95% CI 93.4%-97.9%) and 85.3% (95% CI 74.8%-92.1%) at high-confidence level. The high-confidence level was the strongest predictor of real-time diagnostic accuracy (odds ratio 12.66, P

Objective Sessile serrated adenoma/polyps (SSA/P) are recognized as precancerous lesions in the colon and resemble hyperplastic polyps (HP). Definite endoscopic features under narrow band imaging (NBI) with or without magnification may help differentiate these two lesions. Our study aimed to identify specific endoscopic features of SSA/P by NBI. Methods A total of 199 patients with histopathologically proven colorectal SSA/P or HP after a polypectomy were enrolled. Magnifying and non-magnifying NBI pictures of 206 matching lesions were evaluated by one expert and two non-expert endoscopists using various endoscopic characteristics retrospectively. Results Multivariate analysis indicated that a clouded surface (odds ratio [OR] 6.48, 95% confidence interval [CI] 2.72-15.44, P = 0.000) and dilated and branching vessels (DBV) (OR 7.95, 95% CI 3.71-17.02, P = 0.000) were significant endoscopic features for diagnosing SSA/P compared with HP. The combination of these two features could improve diagnostic specificity to 96%, and the area under the receiver operating characteristic curve was 0.749. However, it seemed that the presence of dark spots (OR 1.93, 95% CI 0.94-4.00, P = 0.075) was not a definite feature in differentiating these two lesions. Neither a mucus cap nor CP-II meshed capillary vessels showed statistical significance in differentiating SSA/P from HP (P = 0.590 and 0.293, respectively). Conclusions A clouded surface and DBV were two indicators for diagnosing SSA/P. Combining these two factors together under NBI with or without magnification achieved better diagnostic performance than when they were used alone.

Reported herein is the rhodium-catalyzed enantioselective C-H bond silylation of the cyclopentadiene rings in Fe and Ru metallocenes. Thus, in the presence of (S)-TMS-Segphos, the reactions took place under very mild conditions to afford metallocene-fused siloles in good to excellent yields and with ee values of up to 97%. During this study it was observed that the steric hindrance of chiral ligands had a profound influence on the reactivity and enantioselectivity of the reaction, and might hold the key to accomplishing conventionally challenging asymmetric C-H silylations.

We developed an efficient and enantioselective method for the synthesis of chiral α-silyl amines. In the presence of a copper(I)-chiral monodentate N-heterocyclic carbene complex (5 mol %), smooth nucleophilic silicon transfer from Me2PhSiBpin (pin=pinacolato) to tosyl-protected aldimines affords the corresponding α-silyl amines in 77–93 % yields over 15 examples and satisfactory ee of 79–99 %. The asymmetric silylation of ketimines was also explored.

Siloles represent an important emerging class of photoluminescent materials. Reported herein is a new synthetic strategy involving a tandem cyclization/Si-C activation reaction featuring high efficiency, wide substrate scope, and practical utility. This method enabled the first synthesis of benzofuran siloles as well as rapid access to conjugated siloles. During the course of the study we also uncovered an unusual yet general Si-C(sp(2)) activation in the presence of π acids.

A highly chemoselective one-pot reaction has been developed involving a tandem semipinacol rearrangement/oxa-Michael addition sequence in which the in situ generated ketol diene intermediate can be transformed specifically to either the spiro- or fused-dihydrofuran products (see scheme). This one-pot tandem reaction represents a general synthetic methodology for the syntheses of the two different kinds of furan derivatives.

The synthesis of mono-, di-, and trifluoromethyl aryl ethers by fluorodecarboxylation of the corresponding carboxylic acids is reported. AgF2 induces decarboxylation of aryloxydifluoroacetic acids, and AgF, either generated in situ or added separately, serves as a source of fluorine to generate the fluorodecarboxylation products. The addition of 2,6-difluoropyridine increased the reactivity of AgF2 , thereby increasing the range of functional groups and electronic properties of the aryl groups that are tolerated. The reaction conditions used for the formation of trifluoromethyl aryl ethers also served to form difluoromethyl and monofluoromethyl aryl ethers.

Two new compounds, 11,11′-dimer of scopoletin ( 1 ) and 11- O - β -glucopyranosylhamaudol ( 2 ), together with seven known compounds were isolated and identified from the whole grass of Cicuta virosa . The chemical structures of the isolated compounds were elucidated using different spectroscopic methods. In addition, the chemical constituents were evaluated for multidrug resistance reversing activity towards doxorubicin-resistant K562/A02 cells. Compounds 1 , 8 , and 9 were endowed with remarkable MDR reversing effects.

Silacyclobutane was discovered to be an efficient C−H bond silylation reagent. Under the catalysis of RhI/TMS-segphos, silacyclobutane undergoes sequential C−Si/C−H bond activations, affording a series of π-conjugated siloles in high yields and regioselectivities. The catalytic cycle was proposed to involve a rarely documented endocyclic β-hydride elimination of five-membered metallacycles, which after reductive elimination gave rise to a Si−RhI species that is capable of C−H activation.

Herein we report a Rh(I)-catalyzed two carbon insertion into C–C bonds of benzocyclobutenols by employing symmetrical and unsymmetrical allenes. This reaction provides rapid access to alkylidene tetralins bearing two adjacent stereogenic centers in good yields and diasteroselectivities.

An asymmetric fluorination/semipinacol rearrangement of 2-oxa allylic alcohols, as catalyzed by cinchona-alkaloid derivatives, gives chiral β-fluoro ketones with moderate to high levels of enantioselectivity (see scheme). Both enantiomers of the product could be obtained by using the appropriate catalyst.

A highly efficient and practical new synthetic strategy for the synthesis of structurally diverse siloles, including the first examples of benzofuran siloles [(XI) and (XII)], is developed.

A highly chemoselective one-pot reaction has been developed involving a tandem semipinacol rearrangement/oxa-Michael addition sequence in which the in situ generated ketol diene intermediate can be transformed specifically to either the spiro- or fused-dihydrofuran products (see scheme). This one-pot tandem reaction represents a general synthetic methodology for the syntheses of the two different kinds of furan derivatives.

The title reaction affords a complex tricyclic system with four continuous stereogenic centers.

Diaryl allylic tertiary alcohols afford up to 93% enantioselectivity by use of a cinchona-derived catalyst and NBS as brominating reagent.

High stereoselectivity in an aqueous medium, the introduction of tri-oxygenated functional groups, and the efficient construction of at least two chiral centers are features of this transformation.

The reaction allows the construction of two adjacent stereocenters: a chiral oxo-quaternary carbon, and a functionalizable halogen.

The formation of the target compounds proceeds via formation of triazoline intermediates and subsequent 1,2-migration.

An efficient first approach to the Stemona alkaloid (±)-Stemonamine has been developed on the basis of a key TiCl4 promoted tandem Semipinacol rearrangement/Schmidt reaction and a Dieckmann condensation reaction.