Prediction rule for estimating advanced colorectal neoplasm risk in average-risk populations in southern Jiangsu Province

Objective：The aim of this study was to establish the risk scoring system towards the advanced colorectal neoplasm （CN） risk in the average-risk populations in the southern Jiangsu Province,and to evaluate the screening efficacy.Methods：Totally 905 cases of the average-risk populations who received the colonoscopy were selected as the objective.The multivariate logistic regression analysis method was used to establish the scoring system towards the occurrence risk of the advanced tumor,and its screening efficacy was evaluated through the prediction consistency,distinguishing ability and screening accuracy.Results：The scoring system consisted of five variables,namely age,gender,coronary heart disease,egg intake and stool frequency.The results revealed that it had good prediction consistency （P=0.205） and distinguishing ability [the area under the receiver operating characteristic （ROC） curve was 0.75,with 95％ confidence interval （95％ CI） of 0.69-0.82].Thus,2.5 points was set as the screening cutoff value,and its sensitivity,specificity,accuracy,positive predictive value,negative predictive value,positive likelihood ratio and negative likelihood ratio were 93.8 ％,47.6％,50.1％,9.1％,99.3％,1.79 and 0.13,respectively.Conclusions：The established scoring system had good screening efficacy,and can be used as the screening tool applying to the CN screening within the average-risk populations in the southern Jiangsu Province.

Gold-catalyzed ketene dual functionalization and mechanistic insights:divergent synthesis of indenes and benzo[d]oxepines

An unprecedented gold-catalyzed ketene C=O/C=C bifunctionalization method has been developed.Mechanistic studies and density function theory(DFT)calculations indicate that the reaction is initiated by gold-catalyzed Wolff rearrangement of diazoketone to form the ketene intermediate,followed by intermolecular nucleophilic addition and terminated with two divergent cyclization processes via enol intermediates.In the case with alcohols as the nucleophiles,the reaction goes through a C-5-endodig carbocyclization to give the indene products;whereas,O-7-endo-dig cyclization occurs dominantly when indoles/pyrroles are used as the nucleophiles,delivering the 7-membered benzo[d]oxepines.In comparison with the well-documented cycloaddition and nucleophilic addition reactions,this cascade reaction features a novel reaction pattern for the ketene dual functionalization through addition with nucleophile and electrophile in sequence.

Recent advances in gold-complex and chiral organocatalyst cooperative catalysis for asymmetric alkyne functionalization

Homogeneous gold catalysis has demonstrated the preponderant capability of realizing a broad range of synthetically versatile alkyne functionalization over the last two decades.Though catalytic asymmetric alkyne transformation has focused on the principle of using gold catalysts either associated with chiral phosphine ligand or combined with chiral counterion,a variety of breakthroughs have been reported with the application of gold-complex and chiral organocatalyst cooperative catalysis strategy,which could enable the challenging transformations that cannot be realized by mono-catalysis with excellent stereoselectivity.This review will cover two general protocols in this field,including relay catalysis and synergistic catalysis,with emphasis on the detailed cooperative catalysts models to illustrate the roles of the two catalysts and highlight the potential synthetic opportunities offered by asymmetric cooperative catalysis.

Highly Enantioselective Trapping of Carboxylic Oxonium Ylides with Imines for Direct Assembly of Enantioenriched γ-Butenolides

Enantioenrichedγ-butenolides are valuable structural cores in many pharmaceuticals and natural products,but their direct and catalytically asymmetric assembly remains rare.Here,we report an efficient,atom-economic synthetic strategy for enantioenrichedγ-butenolides via a unique enantioselective reaction of cyclopropene carboxylic acids with imines under the synergistic catalysis of Rh2(esp)2/chiral Brønsted acid system.The reaction involved trapping of carboxylic oxonium ylides,generated from cyclopropene carboxylic acids,which presented as the first asymmetric trapping reactive intermediate in the process.

Asymmetric Three-Component Propargyloxylation for Direct Assembly of Polyfunctionalized Chiral Succinate Derivatives

An enantioselective three-component propargyloxylation reaction of propargyl alcohols,pyridotriazoles,and imines has been realized by cooperative catalysis with dirhodium complex and chiral phosphoric acid under mild conditions.This is the first example of a catalytic asymmetric three-component propargyloxylation reaction,which provides practical access to chiral polyfunctionalized succinate derivatives with adjacent quaternary and tertiary stereocenters in good to high yields with excellent enantioselectivity.In addition to the alkyne motif,pyridyl,alkoxy,amino,and alkenyl species are all tolerated under the reaction conditions.Notably,the utility of the current method is demonstrated by catalytic cyclization of the product alkyne into a variety of heterocyclic structures without loss of enantiomeric purity.