Use of Eltrombopag to Improve Thrombocytopenia and Tranfusion Requirement in Anti-CD19 CAR-T Cell-Treated Patients.

Background/Objectives: Immune effector cell-associated hematotoxicity (ICAHT) is a frequent adverse event after chimeric antigen receptor (CAR)-T cell therapy. Grade ≥ 3 thrombocytopenia occurs in around one-third of patients, and many of them become platelet transfusion-dependent. Eltrombopag is a thrombopoietin receptor agonist (TPO-RA) able to accelerate megakaryopoiesis, which has been used successfully in patients with bone marrow failure and immune thrombocytopenia (ITP). Its role in managing thrombocytopenia and other cytopenias in CAR-T cell-treated patients has been scarcely addressed. Our aim was to report the safety and efficacy of this approach in patients included in the Spanish Group for Hematopoietic Transplantation and Cellular Therapy (GETH-TC) registry. Methods: This is a retrospective, multicenter, observational study. Patients who developed platelet transfusion dependence subsequently to CAR-T cells and received eltrombopag to improve platelet counts were recruited in 10 Spanish hospitals. Results: Thirty-eight patients were enrolled and followed up for a median (interquartile range [IQR]) of 175 (99, 489) days since CAR-T cell infusion. At the moment eltrombopag was indicated, 18 patients had thrombocytopenia and another severe cytopenia, while 8 patients had severe pancytopenia. After 32 (14, 38) days on eltrombopag, 29 (76.3%) patients recovered platelet transfusion independence. The number of platelet units transfused correlated with the time needed to restore platelet counts higher than 20 × 109/L (Rho = 0.639, p < 0.001). Non-responders to eltrombopag required more platelet units (58 [29, 69] vs. 12 [6, 26] in responders, p = 0.002). Nineteen out of twenty-three (82.6%) patients recovered from severe neutropenia after 22 (11, 31) days on eltrombopag. Twenty-nine out of thirty-five (82.9%) patients recovered red blood cell (RBC) transfusion independence after 29 (17, 44) days. Seven patients recovered all cell lineages while on treatment. No thromboembolic events were reported. Only two transient toxicities (cholestasis, hyperbilirubinemia) were reported during eltrombopag treatment, none of which compelled permanent drug withdrawal. Conclusions: Eltrombopag could be safely used to manage thrombocytopenia and accelerate transfusion independence in CAR-T cell-treated patients.

Sinusoidal Obstruction Syndrome/Veno-Occlusive Disease after Unmanipulated Haploidentical Hematopoietic Stem Cell Transplantation with Post-Transplantation Cyclophosphamide: A Study on Behalf of the Spanish Hematopoietic Stem Cell Transplantation and Cellular Therapy Group (GETH).

Sinusoidal obstruction syndrome/veno-occlusive disease (SOS/VOD) is a life-threatening complication after both autologous and allogeneic hematopoietic stem cell transplantation (HSCT). However, its characterization after haploidentical HSCT (haplo-HSCT) with post-transplantation cyclophosphamide (PT-Cy) is scarce. This study aimed to describe characteristics and outcomes of patients with SOS/VOD after haplo-HSCT with PT-Cy. We conducted a retrospective study of 797 patients undergoing a haplo-HSCT with PT-Cy between 2007 and 2019 in 9 centers in Spain. SOS/VOD was defined according to modified Seattle, Baltimore, or revised European Society for Blood and Marrow Transplantation (EBMT) criteria. Severity was graded retrospectively according to revised EBMT severity criteria into 4 categories: mild, moderate, severe, and very severe. From a total of 797 haplo-HSCTs performed, 46 patients (5.77%) were diagnosed with SOS/VOD at a median of 19 days (range, 4 to 84 days) after transplantation. Based on revised EBMT severity criteria, the SOS/VOD cases were classified as mild (n = 4; 8.7%), moderate (n = 10; 21.7%), severe (n = 12; 26.1%), and very severe (n = 20; 43.5%). Overall, 30 patients (65%) achieved SOS/VOD complete response, 25 (83%) of whom were treated with defibrotide. Twenty patients (43%) died before day +100 post-HSCT. Death was attributed to SOS/VOD in 11 patients, and 5 patients died of other causes without resolution of SOS/VOD. The incidence of SOS/VOD after haplo-HSCT with PT-Cy was comparable to those reported after HLA-identical HSCT series. Most of the patients developed very severe SOS/VOD according to revised EBMT severity criteria. Despite a promising SOS/VOD complete response (CR) rate (65%), 100-day mortality remained high (43%), indicating that further improvement in the management of this potentially fatal complication is needed.

Trans-Concerted Addition to Alkynes: the case of Ynamide Silylzincation.

An original concerted antarafacial mechanism for the addition of diorganosilyl-zinc reagents across the C-C triple bond of ynamides is computationally investigated using DFT calculations. This concerted mechanism, leading to a trans-product in only one step, results in the formation of a Si-C and a Zn-C σ-bond on opposite sides of the π-system. We demonstrate that the mechanism going through a η2-vinyl intermediate and the proposal of a radical chain pathway are energetically unsustainable. The retained concerted antarafacial pathway is tested on experimental selectivities: the regioselectivity, in favor of the silyl ß-addition in ynamide, and stereoselectivity, which is cis- with (Me2PhSi)2Zn but trans- with [(Me3Si)3Si]2Zn, are well reproduced by DFT calculations. The regio- and stereoselectivity are discussed using the activation strain model and a chemical bonding analysis.

α-(Aminomethyl)acrylates as acceptors in radical-polar crossover 1,4-additions of dialkylzincs: insights into enolate formation and trapping.

We demonstrate that α-(aminomethyl)acrylates are suitable acceptors for 1,4-additions of dialkylzincs in aerobic conditions. The air-promoted radical-polar crossover process involves the 1,4-addition of an alkyl radical followed by homolytic substitution at the zinc atom of dialkylzinc. Coordination of the nitrogen atom to zinc enables this SH2 process which represents a rare example of alkylzinc-group transfer to a tertiary α-carbonyl radical. The zinc enolate thus formed readily undergoes ß-fragmentation unless it is trapped by electrophiles in situ. Enolates of substrates having free N-H bonds undergo protodemetalation to provide ultimately the 1,4-addition adduct. In the presence of carbonyl acceptors, aldol condensation occurs providing overall a tandem 1,4-addition-aldol process. When a tert-butanesulfinyl moiety is present on the nitrogen atom, these electrophilic substitution reactions occur with good levels of chiral induction, paving the way to enantioenriched ß2-amino acids and ß2,2-amino acids.

Enantioselective Sequential Catalytic Arylation-Fukuyama Cross-coupling of 1,1-Biszincioalkane Linchpins.

1,1-Bis(iodozincio)alkanes are used as dinucleophilic linchpins in an enantioselective double cross-coupling reaction sequence involving aryl iodides and then thioesters. The two catalytic C-C bond-forming reactions are achieved in the same pot through two distinct palladium-based catalytic systems: a first non-enantioselective one delivering configurationally labile secondary benzylzinc species from an achiral precursor, and a second enantioconvergent one that operates a highly efficient dynamic kinetic resolution of the racemic intermediates. This strategy, new in the area of asymmetric synthesis through two consecutive electrophilic substitution reactions of geminated C(sp3 )-organodimetallics, provides useful methodology to access in a modular fashion acyclic α-disubstituted ketone products with very high enantiomeric purity.

Toxicity of Asciminib in Real Clinical Practice: Analysis of Side Effects and Cross-Toxicity with Tyrosine Kinase Inhibitors.

(1) Background: Despite the prognostic improvements achieved with tyrosine kinase inhibitors (TKIs) in chronic myeloid leukemia (CML), a minority of patients still fail TKIs. The recent introduction of asciminib may be a promising option in intolerant patients, as it is a first-in-class inhibitor with a more selective mechanism of action different from the ATP-competitive inhibition that occurs with TKIs. Therefore, our goal was to analyze toxicities shown with asciminib as well as to study cross-toxicity with previous TKIs. (2) Methods: An observational, multicenter, retrospective study was performed with data from 77 patients with CML with therapeutic failure to second-generation TKIs who received asciminib through a managed-access program (MAP) (3) Results: With a median follow-up of 13.7 months, 22 patients (28.5%) discontinued treatment: 32% (7/22) due to intolerance and 45% (10/22) due to resistance. Fifty-five percent of the patients reported adverse effects (AEs) with asciminib and eighteen percent grade 3-4. Most frequent AEs were: fatigue (18%), thrombocytopenia (17%), anemia (12%), and arthralgias (12%). None of the patients experienced cardiovascular events or occlusive arterial disease. Further, 26%, 25%, and 9% of patients required dose adjustment, temporary suspension, or definitive discontinuation of treatment, respectively. Toxicities under asciminib seemed lower than with prior TKIs for anemia, cardiovascular events, pleural/pericardial effusion, diarrhea, and edema. Cross-toxicity risk was statistically significant for thrombocytopenia, anemia, neutropenia, fatigue, vomiting, and pancreatitis. (4) Conclusion: Asciminib is a molecule with a good safety profile and with a low rate of AEs. However, despite its new mechanism of action, asciminib presents a risk of cross-toxicity with classical TKIs for some AEs.

Modular synthesis of 2-furyl carbinols from 3-benzyldimethylsilylfurfural platforms relying on oxygen-assisted C-Si bond functionalization.

3-Silylated furfurals, readily prepared in three steps from biomass-derived furfural and 5-methylfurfural, are converted into 3-silylated 2-furyl carbinols upon condensation with organomagnesium or organolithium reagents. The hydroxy unit of the carbinol adducts can be exploited to promote C3(sp2)-Si bond functionalization through intramolecular activation. Two approaches were contemplated for this purpose. Activation by alkoxides of the C3-SiEt3 or C3-SiMe2 t-Bu bonds was ineffective. Conversely, treatment of the C3-benzyldimethylsilyl-appended derivatives with tetrabutylammonium fluoride led to cyclic siloxanes, which revealed to be competent donors for copper-catalyzed cross-coupling reactions, such as arylation reactions catalyzed by Pd2(dba)3/CuI, as well as allylation and methylation reactions catalyzed by CuI⋅PPh3. C3-Benzyldimethylsilyl-appended furfurals are thus introduced as versatile platforms, providing a modular access to 3-substituted 2-furyl carbinols from renewable feedstock.

Humoral/Cellular Immune Discordance in Stem Cell Donors: Impact on Cytomegalovirus-Specific Immune Reconstitution after Related Hematopoietic Transplantation.

Cytomegalovirus (CMV) reactivation is an important cause of complications after hematopoietic stem cell transplantation (HSCT). Discrepancies between serologic and cellular CMV-specific immune response have been reported. This study evaluated the impact of lack of CMV-specific CD8+ T cell response in seropositive donors (ie, discordant donors) on the reconstitution of CMV-specific cell-mediated immunity (CMI) after related HSCT in seropositive recipients. CMV-CMI was assessed in donors and recipients using the QuantiFERON-CMV assay (QF). CMV-CMI was prospectively assessed for 1 year in 81 CMV-seropositive HSCT recipients with a haploidentical or matched related donor. A Cox proportional hazard regression analysis was performed. Of the 67 CMV-seropositive donors, 54 (80.6%) were D+QFpos. The remaining 13 CMV-seropositive donors (19.4%) had a QFneg result and thus were classified as discordant donors (D+QFneg). We found that patients with D+QFneg had a significantly higher risk of impaired CMV-CMI reconstitution compared with patients with D+QFpos (log-rank test, P = .001) or D- donors (log-rank test, P = .023). In addition, the D+QFneg group had a higher incidence of single-episode reactivation compared with D+QFpos or D- donors (69.2% versus 44.4% and 28.6%, respectively) but a lower incidence of CMV recurrence compared with the D- group (7.7% versus 57.1%; P = .003). After adjusting for other relevant variables, immune discordance in donors was independently associated with impaired CMV-CMI reconstitution compared with D+QFpos donors (adjusted hazard ratio [HR], 0.18; 95% confidence interval [CI], .06 to .52; P = .001) and D- donors (adjusted HR, .17; 95% CI, .05 to .59; P = .005). Discordant donors were associated with undetectable CMV-CMI during the 12-month follow-up period using the QF assay. The inability of these patients to become QFpos persisted even after CMV reactivation. This might be related to the low frequency of CMV recurrence in this group. CMV-CMI assessment, in conjunction with CMV serostatus, can be of utility to better classify stem cell donors as well as the risk of impaired CMV-CMI reconstitution after HSCT.

Modular access to substituted germoles by intramolecular germylzincation.

Intramolecular alkyne germylzincation giving access to a wide range of germoles is achieved from triarylhydrogermanes in the presence of diethylzinc and AIBN as radical initiator. The reaction proceeds through activation of the Ge-H bond, leading to a heteroarylzinc intermediate after cyclisation, which can then be involved in a post-functionalisation reaction. Our results show that only 5-endo-dig cyclizations occur, with benzogermoles being exclusively obtained.

Synergy of the Tropical Earthworm Pontoscolex corethrurus and Oil Palm Bagasse in the Removal of Heavy Crude Oil.

The tropical endogeic earthworm Pontoscolex corethrurus, a non-standard species used in ecotoxicity, has been found in crude oil-contaminated habitats. We estimated the removal of total hydrocarbons from heavy crude "Maya" oil on an artificially contaminated soil with a median lethal concentration of P. corethrurus and an addition of oil palm bagasse. P. corethrurus had a high survival rate, and the addition of oil palm bagasse led to a greater growth and an increase in abundance of bacteria and fungi. The activity of P. corethrurus and the nutritional quality of oil palm bagasse had a significant impact on the removal of a larger amount of petroleum hydrocarbons from contaminated soil. We concluded that the endogeic earthworm P. corethrurus and oil palm bagasse acted synergistically to achieve a more effective removal of total petroleum hydrocarbons from soil. These results show the potential for using P. corethrurus to remove, either directly or indirectly, crude oil from soil.

Radical Germylzincation of Aryl- and Alkyl-Substituted Internal Alkynes.

The stereoselective germylzincation of internal alkynes delivering trisubstituted vinylgermanes is achieved via a radical chain process involving Ph3GeH and Et2Zn with AIBN as the initiator. Excellent levels of regiocontrol are observed for nonsymmetric (aryl, alkyl)-substituted alkynes and for propargylic alcohols with aryl-, alkyl-, or silyl-substituted alkynes. The germylzincation reaction can be combined in one pot with the Cu(I)-mediated electrophilic substitution of the C(sp2)-Zn bond to obtain synthetically challenging tetrasubstituted vinylgermanes.

Allogeneic Stem Cell Transplantation in Mature T Cell and Natural Killer/T Neoplasias: A Registry Study from Spanish GETH/GELTAMO Centers.

Despite advances in understanding the biology of mature T and natural killer (NK)/T cell neoplasia, current therapies, even the most innovative ones, are still far from ensuring its cure. The only treatment to date that has been shown to control aggressive T cell neoplasms in the long term is allogeneic stem cell transplantation (alloSCT). We aim to report the results of alloSCT for advanced mature T and NK/T neoplasias performed in centers from our national GELTAMO/GETH (Grupo Español de Linfoma y Trasplante de Médula Ósea/Grupo Español de Trasplante Hematopoyético y Terapia Celular) over the past 25 years. As a secondary objective, we analyzed the results of alloSCT from haploidentical donors. We performed a retrospective analysis of all patients who received an alloSCT in Spanish centers (n = 201) from September 1995 to August 2018. The 2-year overall survival (OS) and disease-free survival (DFS) were 65.5% and 58.2%, respectively. The univariate for OS and DFS showed statistically different hazard ratios for conditioning intensity, response pre-alloSCT, comorbidity index, donor/receptor cytomegalovirus status and Eastern Cooperative Oncology Group (ECOG) pre-alloSCT, but only a better ECOG pre-alloSCT remained significant in the multivariate analysis. There was an increased incidence of relapse in those patients who did not develop chronic graft-versus-host disease (GVHD) and an increased risk of death in those developing moderate to severe acute GVHD. The 1-year nonrelapse mortality was 21.9% and was mainly due to GVHD (30%) and bacterial infections (17%). When comparing unrelated donors with haploidentical donors, we found similar results in terms of OS and DFS. There was, however, a reduction of acute GVHD in the haploidentical group (P = .04) and trend to a reduction of chronic GVHD. In conclusion, alloSCT is the only curative option for most aggressive T cell neoplasias. Haploidentical donors offer similar results to related donors in terms of survival with a reduction of acute GVHD.

Transfusion support in COVID-19 patients: Impact on hospital blood component supply during the outbreak.

BACKGROUND: During the COVID-19 outbreak, most hospitals deferred elective surgical procedures to allow space for the overwhelming number of COVID-19 patient admissions, expecting a decrease in routine blood component requirements. However, because transfusion support needs of COVID-19 patients are not well known, its impact on hospital blood supply is uncertain. The objective of this study was to assess the effect of the COVID-19 pandemic on transfusion demand. STUDY DESIGN AND METHODS: Transfusion records during the peak of the COVID-19 pandemic (March 1-April 30, 2020) were reviewed in our center to assess changes in blood requirements. RESULTS: During this period 636 patients received a total of 2934 blood components, which reflects a 17.6% reduction in transfusion requirements with regard to the same period of 2019, and blood donations in Madrid dropped by 45%. The surgical blood demand decreased significantly during the outbreak (50.2%). Blood usage in the hematology and oncology departments remained unchanged, while the day ward demand halved, and intensive care unit transfusion needs increased by 116%. A total of 6.2% of all COVID inpatients required transfusion support. COVID-19 inpatients consumed 19% of all blood components, which counterbalanced the savings owed to the reduction in elective procedures. CONCLUSION: Although only a minority of COVID-19 inpatients required transfusion, the expected reduction in transfusion needs caused by the lack of elective surgical procedures is partially offset by the large number of admitted patients during the peak of the pandemic. This fact must be taken into account when planning hospital blood supply.

Identification of Immunological Parameters as Predictive Biomarkers of Relapse in Patients with Chronic Myeloid Leukemia on Treatment-Free Remission.

BCR-ABL is an aberrant tyrosine kinase responsible for chronic myeloid leukemia (CML). Tyrosine kinase inhibitors (TKIs) induce a potent antileukemic response mostly based on the inhibition of BCR-ABL, but they also increase the activity of Natural Killer (NK) and CD8+ T cells. After several years, patients may interrupt treatment due to sustained, deep molecular response. By unknown reasons, half of the patients relapse during treatment interruption, whereas others maintain a potent control of the residual leukemic cells for several years. In this study, several immunological parameters related to sustained antileukemic control were analyzed. According to our results, the features more related to poor antileukemic control were as follows: low levels of cytotoxic cells such as NK, (Natural Killer T) NKT and CD8±TCRγß+ T cells; low expression of activating receptors on the surface of NK and NKT cells; impaired synthesis of proinflammatory cytokines or proteases from NK cells; and HLA-E*0103 homozygosis and KIR haplotype BX. A Random Forest algorithm predicted 90% of the accuracy for the classification of CML patients in groups of relapse or non-relapse according to these parameters. Consequently, these features may be useful as biomarkers predictive of CML relapse in patients that are candidates to initiate treatment discontinuation.

Risk factors and outcome of COVID-19 in patients with hematological malignancies.

BACKGROUND: Prognostic factors of poor outcome in patients with hematological malignancies and COVID-19 are poorly defined. PATIENTS AND METHODS: This was a Spanish transplant group and cell therapy (GETH) multicenter retrospective observational study, which included a large cohort of blood cancer patients with laboratory-confirmed SARS-CoV-2 infection through PCR assays from March 1st 2020 to May 15th 2020. RESULTS: We included 367 pediatric and adult patients with hematological malignancies, including recipients of autologous (ASCT) (n = 58) or allogeneic stem cell transplantation (allo-SCT) (n = 65) from 41 hospitals in Spain. Median age of patients was 64 years (range 1-93.8). Recipients of ASCT and allo-SCT showed lower mortality rates (17% and 18%, respectively) compared to non-SCT patients (31%) (p = 0.02). Prognostic factors identified for day 45 overall mortality (OM) by logistic regression multivariate analysis included age > 70 years [odds ratio (OR) 2.1, 95% confidence interval (CI) 1.2-3.8, p = 0.011]; uncontrolled hematological malignancy (OR 2.9, 95% CI 1.6-5.2, p < 0.0001); ECOG 3-4 (OR, 2.56, 95% CI 1.4-4.7, p = 0.003); neutropenia (< 0.5 × 109/L) (OR 2.8, 95% CI 1.3-6.1, p = 0.01); and a C-reactive protein (CRP) > 20 mg/dL (OR 3.3, 95% CI 1.7-6.4, p < 0.0001). In multivariate analysis of 216 patients with very severe COVID-19, treatment with azithromycin or low dose corticosteroids was associated with lower OM (OR 0.42, 95% CI 0.2-0.89 and OR 0.31, 95% CI 0.11-0.87, respectively, p = 0.02) whereas the use of hidroxycloroquine did not show significant improvement in OM (OR 0.64, 95% CI 0.37-1.1, P = 0.1). CONCLUSIONS: In most patients with hematological malignancies COVID-19 mortality was directly driven by older age, disease status, performance status, as well as by immune (neutropenia) parameters and level of inflammation (high CRP). Use of azithromycin and low dose corticosteroids may be of value in very severe COVID-19.

Cytotoxic cell populations developed during treatment with tyrosine kinase inhibitors protect autologous CD4+ T cells from HIV-1 infection.

Tyrosine kinase inhibitors (TKIs) are successfully used in clinic to treat chronic myeloid leukemia (CML). Our group previously described that CD4+ T cells from patients with CML on treatment with TKIs such as dasatinib were resistant to HIV-1 infection ex vivo. The main mechanism for this antiviral activity was primarily based on the inhibition of SAMHD1 phosphorylation, which preserves the activity against HIV-1 of this innate immune factor. Approximately 50% CML patients who achieved a deep molecular response (DMR) may safely withdraw TKI treatment without molecular recurrence. Therefore, it has been speculated that TKIs may induce a potent antileukemic response that is maintained in most patients even one year after treatment interruption (TI). Subsequent to in vitro T-cell activation, we observed that SAMHD1 was phosphorylated in CD4+ T cells from CML patients who withdrew TKI treatment more than one year earlier, which indicated that these cells were now susceptible to HIV-1 infection. Importantly, these patients were seronegative for HIV-1 and seropositive for cytomegalovirus (CMV), but without CMV viremia. Although activated CD4+ T cells from CML patients on TI were apparently permissive to HIV-1 infection ex vivo, the frequency of proviral integration was reduced more than 12-fold on average when these cells were infected ex vivo in comparison with cells isolated from untreated, healthy donors. This reduced susceptibility to infection could be related to an enhanced NK-dependent cytotoxic activity, which was increased 8-fold on average when CD4+ T cells were infected ex vivo with HIV-1 in the presence of autologous NK cells. Enhanced cytotoxic activity was also observed in CD8 + T cells from these patients, which showed 8-fold increased expression of TCRγδ and more than 18-fold increased production of IFNγ upon activation with CMV peptides. In conclusion, treatment with TKIs induced a potent antileukemic response that may also have antiviral effects against HIV-1 and CMV, suggesting that transient use of TKIs in HIV-infected patients could develop a sustained antiviral response that would potentially interfere with HIV-1 reservoir dynamics.

Catalytic Chemoselective and Stereoselective Semihydrogenation of Alkynes to E-Alkenes Using the Combination of Pd Catalyst and ZnI2.

An efficient E-selective semihydrogenation of internal alkynes was developed under low dihydrogen pressure and low reaction temperature from commercially available reagents: Cl2Pd(PPh3)2, Zn0, and ZnI2. Kinetic studies and control experiments underline the significant role of ZnI2 in this process under H2 atmosphere, establishing that the transformation involves syn-hydrogenation followed by isomerization. This simple and easy-to-handle system provides a route to E-alkenes under mild conditions.

Radical Germylzincation of α-Heteroatom-Substituted Alkynes.

The regio- and stereoselective addition of germanium and zinc across the C-C triple bond of nitrogen-, sulfur-, oxygen-, and phosphorus-substituted terminal and internal alkynes is achieved by reaction with a combination of R3GeH and Et2Zn. Diagnostic experiments support a radical-chain mechanism and the ß-zincated vinylgermanes that show exceptional stability are characterized by NMR spectroscopy and X-ray crystallography. The unique feature of this new radical germylzincation reaction is that the C(sp2)-Zn bond formed remains available for subsequent in situ Cu(I)- or Pd(0)-mediated C-C or C-heteroatom bond formation with retention of the double bond geometry. These protocols offer modular access to elaborated tri- and tetrasubstituted vinylgermanes decorated with heteroatom substituents ß to germanium that are useful for the preparation of stereodefined alkenes.

Revealing the electrophilicity of N-Ac indoles with FeCl3: a mechanistic study.

Herein, we report a mechanistic exploration of the unusual FeCl3-mediated hydroarylation of N-Ac indoles. Electron density topology analysis of a crystal, in situ IR monitoring, Hammett and Taft studies as well as DFT computations allowed us to determine that activation of acetyl with FeCl3 and of the C2[double bond, length as m-dash]C3 bond with a proton is involved.