Chromium(III)-Catalyzed Desymmetrization of meso-Epoxides via Remote Stereocontrol: Synthesis of Chiral Fluorenes Bearing All-Carbon Quaternary Stereocenters.

An asymmetric desymmetrization of fluorene-derived meso-epoxides is disclosed for the construction of chiral fluorenes bearing an all-carbon quaternary stereocenter at C9. This desymmetrization is catalyzed by a chiral (salen)CrIII complex via remote stereocontrol, producing diverse chiral fluorenes with excellent yields and stereoselectivity. The practicality of this protocol was demonstrated through the transformation of the obtained products to some intriguing enantioenriched polymerizable monomers.

Development and validation of a prognostic score to identify the optimal candidate for preemptive TIPS in patients with cirrhosis and acute variceal bleeding.

BACKGROUND AND AIM: Baveno VII workshop recommends the use of preemptive TIPS (p-TIPS) in patients with cirrhosis and acute variceal bleeding (AVB) at high- risk of treatment failure. However, the criteria defining "high-risk" have low clinical accessibility or include subjective variables. We aimed to develop and externally validate a model for better identification of p-TIPS candidates. APPROACH AND RESULTS: The derivation cohort included 1554 patients with cirrhosis and AVB who were treated with endoscopy plus drug (n = 1264) or p-TIPS (n = 290) from 12 hospitals in China between 2010 and 2017. We first used competing risk regression to develop a score for predicting 6-week and 1-year mortality in patients treated with endoscopy plus drugs, which included age, albumin, bilirubin, international normalized ratio, white blood cell, creatinine, and sodium. The score was internally validated with the bootstrap method, which showed good discrimination (6 wk/1 y concordance-index: 0.766/0.740) and calibration, and outperformed other currently available models. In the second stage, the developed score was combined with treatment and their interaction term to predicate the treatment effect of p-TIPS (mortality risk difference between treatment groups) in the whole derivation cohort. The estimated treatment effect of p-TIPS varied substantially among patients. The prediction model had good discriminative ability (6 wk/1 y c -for-benefit: 0.696/0.665) and was well calibrated. These results were confirmed in the validation dataset of 445 patients with cirrhosis with AVB from 6 hospitals in China between 2017 and 2019 (6-wk/1-y c-for-benefit: 0.675/0.672). CONCLUSIONS: We developed and validated a clinical prediction model that can help to identify individuals who will benefit from p-TIPS, which may guide clinical decision-making.

Pseudo-Diastereodivergent Synthesis of Chiral Fluorenes Bearing Bis-1,3-Nonadjacent Stereogenic Centers via Organocatalytic Desymmetrization of meso-Epoxides.

We report an enantio- and diastereodivergent synthesis of enantioenriched fluorenes bearing bis-1,3-nonadjacent stereocenters with broad substrate scope and high enantioselectivity (up to 99% ee) under low catalyst loading (0.1 mol %). The key to the success of this method is the pseudo-diastereodivergent desymmetrization of stereoisomers of meso-epoxides enabled by the same organocatalyst. Furthermore, some of the chiral fluorenes obtained exhibit high fluorescence quantum yields (up to 76.6%), as evidenced by photophysical properties studies.

Association of nonmalignant portal vein thrombosis and clinical outcomes in patients with cirrhosis and acute variceal bleeding: a multicenter observational study.

BACKGROUND AND AIM: Baveno VII workshop recommends management of acute variceal bleeding (AVB) in cirrhotic patients with nonmalignant portal vein thrombosis (PVT) should be performed according to the guidelines for patients without PVT. Nevertheless, whether PVT affects the outcome of patients with cirrhosis and AVB remains unclear. The aim of this study was to assess the clinical impact of PVT on the outcomes in the pre-emptive TIPSS eligible patients with cirrhosis and AVB. METHODS: From December 2010 to June 2016, 1219 consecutive cirrhotic patients admitted due to AVB with (n = 151; 12.4%) or without PVT (n = 1068; 87.6%), who received drug plus endoscopic treatment (a combination of vasoactive drugs, antibiotics, and endoscopic ligation for AVB, followed by beta-blockers plus variceal ligation for prevention of rebleeding) were retrospectively included. Fine and Gray competing risk regression models were taken to evaluate the impact of PVT on clinical outcomes after adjusting for potential confounders. RESULTS: During follow-up, 211 patients (17.3%) died, 490 (40.2%) experienced further bleeding, and 78 (6.4%) experienced new or worsening ascites within 1 year. Compared with those without PVT, patients with PVT had a similar risk of mortality (PVT vs no-PVT: 19.9% vs 16.7% at 1 year; adjusted HR 0.88, 95%CI 0.51-1.52, p = 0.653), further bleeding (47.0% vs 39.2% at 1 year, adjusted HR 1.19, 95% CI 0.92-1.53, p = 183), and new or worsening ascites (7.9% vs 9.6%, adjusted HR 0.70, 95% CI 0.39-1.28, p = 0.253) after adjusting for confounders in multivariable models. These findings were consistent across different relevant subgroups and confirmed by propensity score matching analysis. CONCLUSIONS: Our study showed no evidence that the PVT was associated with an improved or worsened outcome among cirrhotic patients with AVB who received standard treatment.

Synthesis of a versatile 1H-indene-3-carboxylate scaffold enabled by visible-light promoted Wolff rearrangement of 1-diazonaphthalen-2(1H)-ones.

Herein, we have developed a sequential visible-light-promoted Wolff rearrangement of 1-diazonaphthalen-2(1H)-ones, followed by capturing the in situ generated ketene intermediates with various alcohols, producing diverse 1H-indene-3-carboxylates in moderate to good yields under mild reaction conditions. The broad substrate scope, high functional group tolerance, and robust conditions make the resulting derivative a versatile platform for the synthesis of plenty of bioactive molecules.

Visible-light-induced organocatalytic enantioselective N-H insertion of α-diazoesters enabled by indirect free carbene capture.

While asymmetric insertion of metal carbenes into H-X (X = C, N, O, etc.) bonds has been well-established, asymmetric control over free carbenes is challenging due to the presence of strong background reactions and lack of any anchor for a catalyst interaction. Here we have achieved the first photo-induced metal-free asymmetric H-X bond insertion of this type. With visible light used as a promoter and a chiral phosphoric acid used as a catalyst, α-diazoesters and aryl amines underwent smooth N-H bond insertion to form enantioenriched α-aminoesters with high efficiency and good enantioselectivity under mild conditions. Key to the success was the use of DMSO as an additive, which served to rapidly capture the highly reactive free carbene intermediate to form a domesticated sulfoxonium ylide.

Catalytic asymmetric synthesis of α-tertiary aminoketones from sulfoxonium ylides bearing two aryl groups.

Disclosed herein is an efficient organocatalytic formal N-H insertion reaction of arylamines with α-keto sulfoxonium ylides bearing two aryl groups, delivering a broad range of α-tertiary aminoketones with good to excellent yields and enantioselectivities (up to 90% yield and 94% ee). The utilities of this protocol were also demonstrated by facile preparation of enantioenriched 2-amino-1,2-diarylethanol bearing two different aryl groups, a type of important building block lacking efficient access.

Organocatalytic asymmetric azidation of sulfoxonium ylides: mild synthesis of enantioenriched α-azido ketones bearing a labile tertiary stereocenter.

Disclosed here is a catalytic asymmetric azidation reaction for the efficient synthesis of α-azido ketones bearing a labile tertiary stereocenter. With a superb chiral squaramide catalyst, a mild asymmetric formal H-N3 insertion of α-carbonyl sulfoxonium ylides proceeded with excellent efficiency and enantioselectivity. This organocatalytic process not only complements the previous α-azidation approaches for the formation of quaternary stereocenters and mostly for 1,3-dicarbonyl compounds, but also has advantages over the well-known metal-catalyzed asymmetric carbene insertion chemistry using α-diazocarbonyl compounds. Detailed mechanistic studies via control reactions and NMR studies provided important insights into the reaction pathway, which features reversible protonation and dynamic kinetic resolution. The curiosity in mechanism also led to the development of a simplified alternative protocol with a cheaper HN3 source.

Regioselective α-addition of vinylogous α-ketoester enolate in organocatalytic asymmetric Michael reactions: enantioselective synthesis of Rauhut-Currier type products.

Catalytic asymmetric α-regioselective Michael additions of vinylogous α-ketoester enolate are described herein. With 0.1-1.0 mol% loadings of a chiral bifunctional organocatalyst, the addition of a deconjugated α-keto ester to a series of nitroolefins, including the challenging ß-alkylnitroalkenes, efficiently proceed, providing the Rauhut-Currier type products after isomerization of the terminal double bond in good yields (60-88%) with excellent regio- and enantioselectivities (94-99% ee, TON up to 160 with 0.5 mol% of the catalyst).

CLIF-C AD score predicts survival benefit from pre-emptive TIPS in individuals with Child-Pugh B cirrhosis and acute variceal bleeding.

Background & Aims: Among individuals with Child-Pugh B cirrhosis and acute variceal bleeding (AVB), the Baveno VII workshop recommended pre-emptive TIPS in those with a Child-Pugh score of 8-9 and active bleeding at initial endoscopy (Child B8-9 + AB criteria). Nevertheless, whether this criterion is superior to the CLIF-Consortium acute decompensation score (CLIF-C ADs) remains unclear. Methods: Data on 1,021 consecutive individuals with Child-Pugh B cirrhosis and AVB from 13 university hospitals in China who were treated with pre-emptive TIPS (n = 297) or drug plus endoscopic treatment (n = 724) between 2010 to 2019 were retrospectively analysed. A competing risk regression model was used to compare the outcomes between the two groups after adjusting for confounders. The concordance-statistic for benefit (c-for-benefit) was used to evaluate a models' ability to predict treatment benefit (risk difference between treatment groups). Results: Pre-emptive TIPS was associated with reduced mortality compared to drug plus endoscopic treatment (adjusted hazard ratio 0.62, 95% CI 0.44 to 0.88). A higher baseline CLIF-C AD score was associated with greater survival benefit (i.e., larger absolute mortality risk reduction). After adjusting for confounders, a survival benefit was observed in individuals with CLIF-C ADs ≥48 or Child-Pugh B8-9 with active bleeding, but not in those with CILF-C ADs <48, no active bleeding or Child-Pugh B7 with active bleeding. The c-for-benefit of CILF-C ADs for predicting survival benefit was higher than that of Child B8-9+AB criteria. Conclusions: In individuals with Child-Pugh B cirrhosis and AVB, CLIF-C ADs predicts survival benefit from pre-emptive TIPS and outperforms the Child B8-9+AB criteria. Prospective validation should be performed to confirm this result, especially for other aetiologies of cirrhosis. Impact and implications: In this study, among individuals with Child-Pugh B cirrhosis and acute variceal bleeding, the CLIF-Consortium acute decompensation (CLIF-C AD) score could predict the survival benefit from pre-emptive TIPS, with patients with higher CLIF-C AD scores benefiting more from pre-emptive TIPS. Furthermore, the CLIF-C AD score outperformed the Child B8-9 plus active bleeding criteria in terms of discriminating between those who obtained more benefit vs. less benefit from pre-emptive TIPS. Depending on prospective validation, the CLIF-C AD score could be used as the model of choice to determine who should undergo pre-emptive TIPS.

Lenvatinib with or without Concurrent Drug-Eluting Beads Transarterial Chemoembolization in Patients with Unresectable, Advanced Hepatocellular Carcinoma: A Real-World, Multicenter, Retrospective Study.

Introduction: Lenvatinib is the first-line treatment for advanced hepatocellular carcinoma (HCC). We aimed to compare the clinical outcomes of lenvatinib plus drug-eluting beads transarterial chemoembolization (DEB-TACE) versus lenvatinib alone in real-world practice. Methods: This retrospective analysis included 142 consecutive patients who received lenvatinib plus DEB-TACE and 69 patients who received lenvatinib alone as first-line treatment from 15 Chinese academic centers from November 2018 to November 2019. Overall survival (OS), progression-free survival (PFS), objective response rate (ORR) were evaluated by modified Response Evaluation Criteria in Solid Tumors criteria, and safety profiles were compared between the two groups. Results: The median OS and PFS were significantly longer in the combined therapy group than in the monotherapy group in whole cohort (median OS, 15.9 vs. 8.6 months, p = 0.0022; median PFS, 8.6 vs. 4.4 months, p < 0.001) and after propensity score matching analysis (median OS, 13.8 vs. 7.8 months, p = 0.03; median PFS, 7.8 vs. 4.5 months, p = 0.009). Moreover, the treatment option was an independent prognostic factor for OS and PFS with adjustment based upon baseline characteristics (adjusted hazard ratio [HR]: 0.53, 95% confidence interval [CI]: 0.36-0.78, p = 0.001, and adjusted HR: 0.42, 95% CI: 0.30-0.60, p < 0.001, respectively) and propensity score (adjusted HR: 0.52, 95% CI: 0.36-0.76, p = 0.001, and adjusted HR: 0.46, 95% CI: 0.33-0.64, p < 0.001, respectively). Moreover, a greater ORR was observed in the combined group (ORR: 46.48% vs. 13.05%, p < 0.001). Furthermore, the most common adverse events (AEs) were elevated aspartate aminotransferase (54.9%) and fatigue (46.4%) in the lenvatinib plus DEB-TACE group and lenvatinib group, respectively. Most AEs were mild-to-moderate and manageable. Conclusions: With well-tolerated safety, lenvatinib plus DEB-TACE was more effective than lenvatinib monotherapy in improving OS, PFS, and ORR. Thus, it may be a promising treatment for advanced HCC. Future prospective studies confirming these findings are warranted.

Enantioselective synthesis of triarylmethanes via organocatalytic transfer hydrogenation of para-quinone methides.

A new organocatalytic asymmetric method for the synthesis of enantioenriched triarylmethanes is developed. Different from the conventional approaches featuring asymmetric arylation, the present study employs asymmetric reduction via C-H bond formation as the key step. This approach does not require the presence of a heteroaryl ring or the presynthesis of unstable para-quinone methides. Instead, the stable racemic triarylmethanols were used as substrates for the in situ generation of the intermediates with a suitable chiral phosphoric acid catalyst.

Catalytic Asymmetric Allylic Substitution/Isomerization with Central Chirality Transposition.

We have developed a catalytic asymmetric allylic substitution/isomerization process with central chirality transposition. This process takes advantage of the ambident reactivity of the 2-indole imine methide generated in situ from racemic tertiary indolylmethanols. The use of a suitable chiral phosphoric acid catalyst and an ortho-directing group allowed regioselective formation a C-C bond at the 3 position but enantiocontrolled construction of a stereogenic center at the 2-benzylic position.

Transjugular intrahepatic portosystemic shunt with or without gastro-oesophageal variceal embolisation for the prevention of variceal rebleeding: a randomised controlled trial.

BACKGROUND: The role of variceal embolisation at the time of transjugular intrahepatic portosystemic shunt (TIPS) creation for the prevention of gastro-oesophageal variceal rebleeding remains controversial. This study aimed to evaluate whether adding variceal embolisation to TIPS placement could reduce the incidence of rebleeding after TIPS in patients with cirrhosis. METHODS: We did an open-label, randomised controlled trial at one university hospital in China. Eligible patients were aged 18-75 years with cirrhosis and had variceal bleeding in the past 6 weeks, and they were randomly assigned (1:1) to receive TIPS (with a covered stent in both groups) plus variceal embolisation (TIPS plus embolisation group) or TIPS alone (TIPS group) to prevent variceal rebleeding. Randomisation was done using a web-based randomisation system using a Pocock and Simon's minimisation method, stratified by Child-Pugh class (A vs B vs C). Clinicians and patients were not masked to treatment allocation; individuals involved in data analysis were masked to treatment assignment. The primary endpoint was the 2-year cumulative incidence of variceal rebleeding after randomisation, and analysis was by intention to treat. The trial is registered with ClinicalTrials.gov, NCT02119988. FINDINGS: Between June 16, 2014, and Feb 3, 2016, 205 patients were screened, of whom 134 were randomly allocated to the TIPS plus embolisation group (n=69) and the TIPS group (n=65). TIPS placement and variceal embolisation was successful in all 134 patients, all were included in the analysis. There was no significant difference in the 2-year cumulative incidence of variceal rebleeding between the two groups (TIPS plus embolisation 11·6% [95% CI 4·0-19·1] vs TIPS 13·8% [5·4-22·2]; hazard ratio 0·82 [95% CI 0·42-1·61]; p=0·566). Adverse events were similar between the two groups; the most common adverse events were peptic ulcer or gastritis (12 [17%] of patients in the TIPS plus embolisation group vs 13 [20%] of patients in the TIPS group), new or worsening ascites (ten [14%] vs six [9%]), and hepatocellular carcinoma (four [6%] vs six [9%]). The numbers of deaths were also similar between groups (24 [35%] vs 25 [38%]) INTERPRETATION: Adding variceal embolisation to TIPS did not significantly reduce the incidence of variceal rebleeding in patients with cirrhosis. Our findings do not support concomitant variceal embolisation during TIPS for the prevention of variceal rebleeding. FUNDING: National Key Technology R&D Program, Boost Program of Xijing Hospital, and China Postdoctoral Science Foundation.

Reductive Opening of Oxetanes Catalyzed by Frustrated Lewis Pairs: Unexpected Aryl Migration via Neighboring Group Participation.

B(C6F5)3 was found to catalyze an unusual double reduction of oxetanes by hydrosilane with aryl migration via neighboring group participation. Control experiments suggested that the phenonium ion serves as the key intermediate. Minor modification of this protocol also led to simple hydrosilylative opening of oxetanes.

Optimal time point of response assessment for predicting survival is associated with tumor burden in hepatocellular carcinoma receiving repeated transarterial chemoembolization.

OBJECTIVES: Objective response rate (ORR) under mRECIST criteria after transarterial chemoembolization (TACE) is a well-perceived surrogate endpoint of overall survival (OS). However, its optimal time point remains controversial and may be influenced by tumor burden. We aim to investigate the surrogacy of initial/best ORR in relation to tumor burden. METHODS: A total of 1549 eligible treatment-naïve patients with unresectable hepatocellular carcinoma (HCC), Child-Pugh score ≤ 7, and performance status score ≤ 1 undergoing TACE between January 2010 and May 2016 from 17 academic hospitals were retrospectively analyzed. Based on "six-and-twelve" criteria, tumor burden was graded as low, intermediate, and high if the sum of the maximum tumor diameter and tumor number was ≤ 6, > 6 but ≤ 12, and > 12, respectively. RESULTS: Both initial and best ORRs interacted with tumor burden. Initial and best ORRs could equivalently predict and correlate with OS in low (adjusted HR, 2.55 and 2.95, respectively, both p < 0.001; R = 0.84, p = 0.035, and R = 0.97, p = 0.002, respectively) and intermediate strata (adjusted HR, 1.81 and 2.22, respectively, both p < 0.001; R = 0.74, p = 0.023, and R = 0.9, p = 0.002, respectively). For high strata, only best ORR exhibited qualified surrogacy (adjusted HR, 2.61, p < 0.001; R = 0.70, p = 0.035), whereas initial ORR was not significant (adjusted HR, 1.08, p = 0.357; R = 0.22, p = 0.54). CONCLUSIONS: ORR as surrogacy of OS is associated with tumor burden. For patients with low/intermediate tumor burden, initial ORR should be preferred in its early availability upon similar sensitivity, whereas for patients with high tumor burden, best ORR has optimal sensitivity. Timing of OR assessment should be tailored according to tumor burden. KEY POINTS: • This is the first study utilizing individual patient data to comprehensively analyze the surrogacy of ORR with a long follow-up period. • Optimal timing of ORR assessment for predicting survival should be tailored according to tumor burden. • For patients with low and intermediate tumor burden, initial ORR is optimal for its timeliness upon similar sensitivity with best ORR. For patients with high tumor burden, best ORR has optimal sensitivity.

Restoration of the gut microbiota is associated with a decreased risk of hepatic encephalopathy after TIPS.

Background & Aims: Hepatic encephalopathy (HE) is a major complication after transjugular intrahepatic portosystemic shunt (TIPS) and is primarily influenced by the gut microbiota. We aimed to evaluate alterations in the microbiota after TIPS and the association between such alterations and HE. Methods: We conducted a prospective longitudinal study of 106 patients with cirrhosis receiving TIPS. Faecal samples were collected before and after TIPS, and the gut microbiota was analysed by 16S ribosomal RNA sequencing. Results: Among all patients, 33 developed HE (HE+ group) within 6 months after TIPS and 73 did not (HE- group), and 18 died during follow-up. After TIPS, the autochthonous taxa increased, whereas the potential pathogenic taxa decreased in the HE- group, and the autochthonous taxon Lachnospiraceae decreased in the HE+ group. Furthermore, synergism among harmful bacteria was observed in all patients, which was weakened in the HE- group (p <0.001) but enhanced in the HE+ group (p <0.01) after TIPS. Variations of 5 autochthonous taxa, namely, Coprococcus, Ruminococcus, Blautia, Ruminococcaceae_uncultured, and Roseburia, were negatively correlated with the severity of HE. Notably, increased abundances of Coprococcus and Ruminococcus were protective factors against HE, and the incidences of HE in patients with improved, stable, and deteriorated microbiota after TIPS were 13.3, 25.9, and 68.2%, respectively. Higher total bilirubin level, Child-Pugh score, model for end-stage liver disease score, Granulicatella, and Alistipes and lower Subdoligranulum before TIPS were the independent risk factors for death. Conclusions: Alterations in gut dysbiosis were negatively related to the occurrence and severity of post-TIPS HE, and the pre-TIPS microbiota were associated with death, suggesting the gut microbiota could be a promising potential biological target for screening suitable patients receiving TIPS and prevention and treatment of post-TIPS HE. Lay summary: Alterations in the gut microbiota after transjugular intrahepatic portosystemic shunt (TIPS) and the relationship between such alterations and post-TIPS hepatic encephalopathy (HE) remain unclear. We therefore performed this study and found that after TIPS, restoration of the gut microbiota, mainly characterised by expansion of autochthonous taxa, depletion of harmful taxa, and weakening of synergism among harmful bacteria, was inversely related to the occurrence and severity of post-TIPS HE.

Concurrent large spontaneous portosystemic shunt embolization for the prevention of overt hepatic encephalopathy after TIPS: A randomized controlled trial.

BACKGROUND AND AIMS: Large spontaneous portosystemic shunt (SPSS) is associated with increased risk of HE in patients undergoing transjugular intrahepatic portosystemic shunt (TIPS). This study aimed to evaluate whether prophylactic embolization of large SPSS at the time of TIPS creation could reduce the incidence of post-TIPS HE in patients with cirrhosis and variceal bleeding. APPROACH AND RESULTS: From June 2014 to August 2017, 56 patients with cirrhosis and large SPSS planning to undergo TIPS for the prevention of variceal bleeding were randomly assigned (1:1) to receive TIPS alone (TIPS group, n = 29) or TIPS plus simultaneous SPSS embolization (TIPS+E group, n = 27). The primary endpoint was overt HE. TIPS placement and SPSS embolization was successful in all patients. During a median follow-up of 24 months, the primary endpoint was met in 15 patients (51.7%) in the TIPS group and six patients (22.2%) in the TIPS+E group (p = 0.045). The 2-year cumulative incidence of overt HE was significantly lower in the TIPS+E group compared with the TIPS group (21.2% vs. 48.3%; HR, 0.38; 95% CI, 0.15-0.97; p = 0.043). The 2-year incidence of recurrent bleeding (TIPS+E vs. TIPS, 15.4% vs. 25.1%; p = 0.522), shunt dysfunction (12.3% vs. 18.6%, p = 0.593), death (15.0% vs. 6.9%, p = 0.352), and other adverse events was not significantly different between the two groups. CONCLUSIONS: In patients with cirrhosis treated with TIPS for variceal bleeding, concurrent large SPSS embolization reduced the risk for overt HE without increasing other complications. Concurrent large SPSS embolization should therefore be considered for prophylaxis of post-TIPS HE.

Catalytic Enantioselective Synthesis of 2,3-Dihydrobenzo[b]oxepines via Asymmetric Oxetane Opening by Internal Carbon Nucleophiles.

An intramolecular C-C formation process based on catalytic asymmetric oxetane opening by carbon nucleophiles has been developed, which provides rapid access to a range of valuable enantioenriched 2,3-dihydrobenzo[b]oxepines. With the combination of Sc(OTf)3 and a Box ligand, good chemical efficiency and enantioselectivity were achieved under mild conditions. The products are also useful precursors to other valuable structures, such as the bicyclo[3.2.2]nonane derivatives.