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Novel 4′-substituted β- d -2′-deoxy-2′-α-fluoro (2′d2′F) nucleoside inhibitors of respiratory syncytial virus (RSV) are reported. The introduction of 4′-substitution onto 2′d2′F nucleoside analogs resulted in compounds demonstrating potent cell based RSV inhibition, improved inhibition of the RSV polymerase by the nucleoside triphosphate metabolites, and enhanced selectivity over incorporation by mitochondrial RNA and DNA polymerases. Selectivity over the mitochondrial polymerases was found to be extremely sensitive to the specific 4′-substitution and not readily predictable. Combining the most potent and selective 4′-groups from N -nucleoside analogs onto a 2′d2′F C -nucleoside analog resulted in the identification of β- d -2′-deoxy-2′-α-fluoro-4′-α-cyano-5-aza-7,9-dideaza adenosine as a promising nucleoside lead for RSV. [ABSTRACT FROM AUTHOR]

GS-5806is a novel, orally bioavailable RSV fusion inhibitor discoveredfollowing a lead optimization campaign on a screening hit. The oralabsorption properties were optimized by converting to the pyrazolo[1,5-a]-pyrimidine heterocycle, while potency, metabolic, andphysicochemical properties were optimized by introducing the para-chloro and aminopyrrolidine groups. A mean EC50= 0.43 nM was found toward a panel of 75 RSV A and B clinical isolatesand dose-dependent antiviral efficacy in the cotton rat model of RSVinfection. Oral bioavailability in preclinical species ranged from46 to 100%, with evidence of efficient penetration into lung tissue.In healthy human volunteers experimentally infected with RSV, a potentantiviral effect was observed with a mean 4.2 log10reductionin peak viral load and a significant reduction in disease severitycompared to placebo. In conclusion, a potent, once daily, oral RSVfusion inhibitor with the potential to treat RSV infection in infantsand adults is reported. [ABSTRACT FROM AUTHOR]

Abstract: GS-9148 [(5-(6-amino-purin-9-yl)-4-fluoro-2,5-dihydro-furan-2-yloxymethyl)phosphonic acid] 4 is a novel nucleoside phosphonate HIV-1 reverse transcriptase (RT) inhibitor with a unique resistance profile toward N(t)RTI resistance mutations. To effectively deliver 4 and its active phosphorylated metabolite 15 into target cells, a series of amidate prodrugs were designed as substrates of cathepsin A, an intracellular lysosomal carboxypeptidase highly expressed in peripheral blood mononuclear cells (PBMCs). The ethylalaninyl phosphonamidate prodrug 5 (GS-9131) demonstrated favorable cathepsin A substrate properties, in addition to favorable in vitro intestinal and hepatic stabilities. Following oral dosing (3mg/kg) in Beagle dogs, high levels (>9.0μM) of active metabolite 15 were observed in PBMCs, validating the prodrug design process and leading to the nomination of 5 as a clinical candidate. [Copyright &y& Elsevier]

Abstract: Modified purine analogs of GS-9148 [5-(6-amino-purin-9-yl)-4-fluoro-2,5-dihydro-furan-2-yloxymethyl]-phosphonic acid (2′-Fd4AP) were synthesized and their anti-HIV potency evaluated. The antiviral activity of guanosine analog (2′-Fd4GP) was comparable that of to 2′-Fd4AP in MT-2 cells, but selectivity was reduced. [Copyright &y& Elsevier]

Abstract: GS-9148 (2′-Fd4AP, 4) has been identified as a nucleoside phosphonate reverse transcriptase (RT) inhibitor with activity against wild-type HIV (EC50 =12μM). Unlike many clinical RT inhibitors, relevant reverse transcriptase mutants (M184V, K65R, 6-TAMs) maintain a susceptibility to 2′-Fd4AP that is similar to wild-type virus. The 2′-fluorine group was rationally designed into the molecule to improve the selectivity profile and in preliminary studies using HepG2 cells, compound 4 showed no measurable effect on mitochondrial DNA content indicating a low potential for mitochondrial toxicity. [Copyright &y& Elsevier]

Abstract: A series of nucleoside phosphonate reverse transcriptase (RT) inhibitors have been synthesized and their anti-HIV activity and resistance profiles evaluated. The most potent analog [5-(6-amino-purin-9-yl)-2,5-dihydro-furan-2-yloxymethyl]-phosphonic acid (d4AP) demonstrated a HIV EC50 =2.1μM, and the most favorable resistance profile against HIV-1 variants with K65R, M184V or multiple thymidine analog mutations in RT. [Copyright &y& Elsevier]

Abstract: Phosphonomethoxy nucleoside analogs of the thymine containing nucleoside reverse transcriptase inhibitors (NRTIs), 3′-azido-2′,3′-dideoxythymidine (AZT), 2′,3′-didehydro-2′,3′-dideoxythymidine (d4T), and 2′,3′-dideoxythymidine (ddT), were synthesized. The anti-HIV activity against wild-type and several major nucleoside-resistant strains of HIV-1 was evaluated together with the inhibition of wild-type HIV reverse transcriptase (RT). Phosphonomethoxy analog of d4T, 8 (d4TP), demonstrated antiviral activity with an EC50 value of 26μM, whereas, phosphonomethoxy analogs of ddT, 7 (ddTP), and AZT, 6 (AZTP), were both inactive at concentrations up to 200μM. Bis-isopropyloxymethylcarbonyl (bisPOC) prodrugs improved the anti-HIV activity of 7 and 8 by >150-fold and 29-fold, respectively, allowing for antiviral resistance to be determined. The K65R RT mutant virus was more resistant to the bisPOC prodrugs of 7 and 8 than bisPOC PMPA (tenofovir DF) 1. However, bisPOC prodrug of 7 demonstrated superior resistance toward the RT virus containing multiple thymidine analog mutations (6TAMs) indicating that new phosphonate nucleoside analogs may be suitable for targeting clinically relevant nucleoside resistant HIV-1 strains. [Copyright &y& Elsevier]

The development of potent and selective urokinase-type plasminogen activator (uPA) inhibitors based on the lead molecule 2-(2-hydroxy-3-ethoxyphenyl)-1H-benzimidazole-5-carboxamidine (3a) is described. [Copyright &y& Elsevier]

The article offers information on a randomized clinical trial conducted to observe the activity of GS-5806, which is an inhibitor of respiratory syncytial virus (RSV) that leads to infant hospitalizations, morbidity and mortality. It states that the participants were divided into two groups, one received GS-5806 and other received placebo. It concludes that the treatment of infants with GS-5806 reduced the viral load of RSV.

Graphical abstract Highlights • The structure-guided discovery of a novel BET bromodomain inhibitor is disclosed. • The lead properties were optimized using in-vitro assays and in-vivo PK studies. • The lead compound reduced the in vivo tumor growth two xenograft models. Abstract The bromodomain and extra-terminal (BET) family of proteins, consisting of the bromodomains containing protein 2 (BRD2), BRD3, BRD4, and the testis-specific BRDT, are key epigenetic regulators of gene transcription and has emerged as an attractive target for anticancer therapy. Herein, we describe the discovery of a novel potent BET bromodomain inhibitor, using a systematic structure-based approach focused on improving potency, metabolic stability, and permeability. The optimized dimethylisoxazole aryl-benzimidazole inhibitor exhibited high potency towards BRD4 and related BET proteins in biochemical and cell-based assays and inhibited tumor growth in two proof-of-concept preclinical animal models. [ABSTRACT FROM AUTHOR]

Angularly and peri‐fused tricyclic pyrrolidinopyrazolines are efficiently prepared by LiCl‐catalyzed domino aza‐Michael addition‐1,3‐dipolar cycloaddition reactions. The absolute stereochemistry is controlled in the aza‐Michael addition step, nonaflyl azide serves as effective diazo transfer reagent to the formed enolate and the resulting diazo dipole engages in the 1,3‐dipolar cycloaddition step. The resulting tricyclic pyrrolidinopyrazolines can be easily transformed to enantiomerically enriched nonproteinogenic spirocyclic α,β,γ‐triamino acids, angularly or peri‐fused tricyclic β‐prolines or pyrimidines. The activity of the tricyclic amino acid derivatives against the hepatitis C virus was determined. Angularly and peri‐fused tricyclic pyrrolidinopyrazolines are efficiently prepared by LiCl catalyzed domino aza‐Michael addition‐1,3‐dipolar cycloaddition. The resulting tricyclic pyrrolidinopyrazolines can be easily transformed to spirocyclic or condensed bicyclic α,β,γ‐triamino acid derivatives. [ABSTRACT FROM AUTHOR]

Abstract: Respiratory syncytial virus (RSV)‐associated respiratory tract infection is a leading cause of hospitalizations in infants for which no effective treatment exists. RSV infection is also an important cause of respiratory disease in adults and immunocompromised patients. Presatovir (GS‐5806) is an orally bioavailable antiviral agent that inhibits fusion of RSV with host cell membranes. Here, results from 2 phase 1 studies that evaluated safety, tolerability, and pharmacokinetics of presatovir in healthy adults following administration of single and multiple (7 days) once‐ or twice‐daily ascending doses (first‐in‐human study) and in the presence or absence of food (food effect study) are described. Presatovir exhibited favorable safety and pharmacokinetic profiles that supported once‐daily dosing. Presatovir exposure increased in an approximately dose‐proportional manner across the evaluated dose range (single doses 25‐300 mg; multiple doses 10‐75 mg once daily for 7 days). Administration of presatovir with a high‐fat meal did not alter exposure, supporting administration without regard to a meal in further clinical studies. These data were subsequently used to inform presatovir dosing regimens in a phase 2a challenge study of adults experimentally infected with RSV. Collectively, results from phase 1 evaluations and a phase 2a challenge study support further clinical investigation of presatovir for the treatment of RSV infection. [ABSTRACT FROM AUTHOR]

We describe a novel stereoselective synthesis of nucleoside derivatives with the ribose ring locked in the South conformation by a bridge between C2' and C5'. Despite the intrinsic constraints of the bicyclic structure, we demonstrate that their synthesis can be achieved by ring closing metathesis of readily accessible precursors. The obtained ribose derivatives are, however, very poor substrates for further installation of the nucleobases, and even simple nucleophiles, such as azido or cyano anions, react with unexpected stereo- or regioselectivity under standard glycosylation conditions. Here we explain this behavior by employing density functional theory (DFT) computations and devise an alternative approach resulting in isomers with the desired orientation of the nucleobase. [ABSTRACT FROM AUTHOR]

Enantioselective syntheses of densely functionalized pyrrolidines deriving their chirality from ( R)-1-(phenyl)ethylamine are reported. Allylic amines and β-substituted-α,β-unsaturated esters are used as the building blocks in this one-pot reaction. Single electron transfer (SET) oxidation served to merge the reactivities of anionic enolate and radical intermediates. Ferrocenium hexafluorophosphate, which is easy to prepare, store and handle, was applied as SET oxidant and persistent free radical TEMPO served as the oxygenating agent introducing a protected hydroxy function, which proved to be beneficial for further derivatization. Exclusive 2,3- trans and up to 6:1 3,4- cis/trans diastereoselectivities were achieved in the targeted tetrasubstituted pyrrolidines. [ABSTRACT FROM AUTHOR]

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of the COVID-19 pandemic, has infected over 260 million people over the past 2 years. Remdesivir (RDV, VEKLURY®) is currently the only antiviral therapy fully approved by the FDA for the treatment of COVID-19. The parent nucleoside of RDV, GS-441524, exhibits antiviral activity against numerous respiratory viruses including SARS-CoV-2, although at reduced in vitro potency compared to RDV in most assays. Here we find in both human alveolar and bronchial primary cells, GS-441524 is metabolized to the pharmacologically active GS-441524 triphosphate (TP) less efficiently than RDV, which correlates with a lower in vitro SARS-CoV-2 antiviral activity. In vivo , African green monkeys (AGM) orally dosed with GS-441524 yielded low plasma levels due to limited oral bioavailability of <10%. When GS-441524 was delivered via intravenous (IV) administration, although plasma concentrations of GS-441524 were significantly higher, lung TP levels were lower than observed from IV RDV. To determine the required systemic exposure of GS-441524 associated with in vivo antiviral efficacy, SARS-CoV-2 infected AGMs were treated with a once-daily IV dose of either 7.5 or 20 mg/kg GS-441524 or IV RDV for 5 days and compared to vehicle control. Despite the reduced lung TP formation compared to IV dosing of RDV, daily treatment with IV GS-441524 resulted in dose-dependent efficacy, with the 20 mg/kg GS-441524 treatment resulting in significant reductions of SARS-CoV-2 replication in the lower respiratory tract of infected animals. These findings demonstrate the in vivo SARS-CoV-2 antiviral efficacy of GS-441524 and support evaluation of its orally bioavailable prodrugs as potential therapies for COVID-19. • GS-441524 and remdesivir both inhibit SARS-CoV-2 in primary human lung cells. • Limited oral bioavailability of GS-441524 in primates necessitates IV administration to yield high plasma concentrations. • Intravenous GS-441524 and remdesivir both reduce SARS-CoV-2 viral burden AGM model. • Antiviral efficacy of GS-441524 suggests prodrugs that increase oral bioavailability are desirable to identify and develop. [ABSTRACT FROM AUTHOR]

A simple modular tandem approach to multiply substituted cyclopentane derivatives is reported, which succeeds by joining organometallic addition, conjugate addition, radical cyclization, and oxygenation steps. The key steps enabling this tandem process are the thus far rarely used isomerization of allylic alkoxides to enolates and single-electron transfer to merge the organometallic step with the radical and oxygenation chemistry. This controlled lineup of multiple electronically contrasting reactive intermediates provides versatile access to highly functionalized cyclopentane derivatives from very simple and readily available commodity precursors. The antiviral activity of the synthesized compounds was screened and a number of compounds showed potent activity against hepatitis C and dengue viruses. [ABSTRACT FROM AUTHOR]

The utility of remdesivir treatment in COVID-19 patients is currently limited by the necessity to administer this antiviral intravenously, which has generally limited its use to hospitalized patients. Here, we tested a novel, subcutaneous formulation of remdesivir in the rhesus macaque model of SARS-CoV-2 infection that was previously used to establish the efficacy of remdesivir against this virus in vivo. Compared to vehicle-treated animals, macaques treated with subcutaneous remdesivir from 12 h through 6 days post inoculation showed reduced signs of respiratory disease, a reduction of virus replication in the lower respiratory tract, and an absence of interstitial pneumonia. Thus, early subcutaneous administration of remdesivir can protect from lower respiratory tract disease caused by SARS-CoV-2. • Remdesivir is a nucleotide analog prodrug with broad-spectrum antiviral activity shown to be effective against SARS-CoV-2. • The utility of remdesivir treatment in COVID-19 patients is limited by the necessity to administer it intravenously. • The efficacy of a subcutaneous formulation of remdesivir was tested in the rhesus macaque model of SARS-CoV-2 infection. • Subcutaneous remdesivir reduced respiratory signs, reduced replication in the lungs, and prevented interstitial pneumonia. [ABSTRACT FROM AUTHOR]

Abstract: Ribonucleoside phosphonate analogues containing 2′-α-fluoro modifications were synthesized and their potency evaluated against HCV RNA polymerase. The diphosphophosphonate (triphosphate equivalent) adenine and cytidine analogues displayed potent inhibition of the HCV polymerase in the range of 1.9–2.1μM, but only modest cell-based activity in the HCV replicon. Pro-drugs of the parent nucleoside phosphonates improved the cell-based activity. [Copyright &y& Elsevier]

Abstract: A novel and efficient method for the one-pot synthesis of diamide (bis-amidate) prodrugs of acyclic nucleoside phosphonates, starting from free phosphonic acids or phosphonate diesters is reported. The approach from phosphonate diesters via their bis(trimethylsilyl) esters is highly convenient, eliminates isolation and tedious purification of the phosphonic acids, and affords the corresponding bis-amidates in excellent yields (83–98%) and purity. The methodology has been applied to the synthesis of the potent anticancer agent GS-9219, and symmetrical bis-amidates of other biologically active phosphonic acids. Anti-HIV, antiproliferative, and immunomodulatory activities of the compounds are discussed including the bis-amidate prodrugs 14 and 17 that exhibited anti-HIV activity at submicromolar concentrations with minimal cytotoxicity. [Copyright &y& Elsevier]

Abstract: GS-9148 ([5-(6-amino-purin-9-yl)-4-fluoro-2,5-dihydro-furan-2-yloxymethyl]-phosphonic acid) is a dAMP (2′-deoxyadenosine monophosphate) analog that maintains its antiviral activity against drug-resistant HIV. Crystal structures for HIV-1 reverse transcriptase (RT) bound to double-stranded DNA, ternary complexes with either GS-9148-diphosphate or 2′-deoxyadenosine triphosphate (dATP), and a post-incorporation structure with GS-9148 translocated to the priming site were obtained to gain insight into the mechanism of RT inhibition. The binding of either GS-9148-diphosphate or dATP to the binary RT–DNA complex resulted in the fingers subdomain closing around the incoming substrate. This produced up to a 9 Å shift in the tips of the fingers subdomain as it closed toward the palm and thumb subdomains. GS-9148-diphosphate shows a similar binding mode as dATP in the nucleotide-binding site. Residues whose mutations confer resistance to nucleotide/nucleoside RT inhibitors, such as M184, Y115, L74, and K65, show little to no shift in orientation whether GS-9148-diphosphate or dATP is bound. One difference observed in binding is the position of the central ring. The dihydrofuran ring of GS-9148-diphosphate interacts with the aromatic side chain of Y115 more than does the ribose ring of dATP, possibly picking up a favorable π–π interaction. The ability of GS-9148-diphosphate to mimic the active-site contacts of dATP may explain its effective inhibition of RT and maintained activity against resistance mutations. Interestingly, the 2′-fluoro moiety of GS-9148-diphosphate was found in close proximity to the Q151 side chain, potentially explaining the observed moderately reduced susceptibly to GS-9148 conferred by Q151M mutation. [Copyright &y& Elsevier]

Abstract: A diphosphate of a novel cyclopentyl based nucleoside phosphonate with potent inhibition of HIV reverse transcriptase (RT) (20, IC50 =0.13μM) has been discovered. In cell culture the parent phosphonate diacid 9 demonstrated antiviral activity EC50 =16μM, within two-fold of GS-9148, a prodrug of which is currently under clinical investigation, and within 5-fold of tenofovir (PMPA). In vitro cellular metabolism studies using 9 confirmed that the active diphosphate metabolite is produced albeit at a lower efficiency relative to GS-9148. [Copyright &y& Elsevier]

Abstract: An efficient and facile synthesis of a large series of diverse 6-(N-substituted aminomethyl)-, 6-(O-substituted hydroxymethyl)- and 6-(S-substituted sulfanylmethyl)purine nucleosides (55 examples of both ribo- and 2′-deoxyribonucleosides), aimed at identifying novel homologues of natural nucleosides, was developed. The key transformation involved nucleophilic substitutions of Tol-protected 6-(mesyloxymethyl)purine nucleosides by primary or secondary amines, alcoholates or thiolates. While the 2′-deoxyribonucleosides were inactive, the ribonucleosides exerted considerable cytostatic effects and some anti-HCV activity with low selectivity. [Copyright &y& Elsevier]

Abstract: An efficient and facile synthesis of a large series of diverse 6-[2-(dialkylamino)vinyl]-, 6-[2-(dialkylamino)ethyl]-, 6-(2-alkoxyethyl)-, and 6-[2-(alkylsulfanyl)ethyl]purine nucleosides (35 examples of both ribo- and 2′-deoxyribonucleosides) was developed. The key transformations involved conjugate nucleophilic additions of amines, alcoholates, or thiolates to Tol-protected 6-alkylylpurine or 6-vinylpurine nucleosides. 6-[(2-Dialkylamino)vinyl]- and some 6-[(2-dialkylamino)ethyl]purine ribonucleosides exerted significant cytostatic effects and some anti-HCV activity with low selectivity. [Copyright &y& Elsevier]

Abstract: A series of purine l-ribonucleosides 2a–2i bearing diverse C-substituents (alkyl, aryl, hetaryl or hydroxymethyl) in the position 6 were prepared by Pd-catalyzed cross-coupling reactions of 6-chloro-9-(2,3,5-tri-O-acetyl-β-l-ribofuranosyl)purine with the corresponding organometallics followed by deprotection. Unlike their d-ribonucleoside enantiomers that possess strong cytostatic and anti-HCV activity, the l-ribonucleosides were inactive except for 6-benzylpurine nucleoside 2h showing moderate anti-HCV effect in replicon assay. A triphosphate of 2h did not inhibit HCV RNA polymerase. [Copyright &y& Elsevier]

A site-directed mutant of the serine protease urokinase-type plasminogen activator (uPA), was produced to assess the contribution of the Ser190 side-chain to the affinity and selectivity of lead uPA inhibitors in the absence of other differences present in comparisons of natural proteases. Crystallography and enzymology involving WT and Ala190 uPA were used to calculate free energy binding contributions of hydrogen bonds involving the Ser190 hydroxyl group (OγSer190) responsible for the remarkable selectivity of 6-halo-5-amidinoindole and 6-halo-5-amidinobenzimidazole inhibitors toward uPA and against natural Ala190 protease anti-targets. Crystal structures of uPA complexes of novel, active site-directed arylguanidine and 2-aminobenzimidazole inhibitors of WT uPA, together with associated Ki values for WT and Ala190 uPA, also indicate a significant role of Ser190 in the binding of these classes of uPA inhibitors. Structures and associated Ki values for a lead inhibitor (CA-11) bound to uPA and to five other proteases, as well as for other leads bound to multiple proteases, help reveal the features responsible for the potency (Ki=11nM) and selectivity of the remarkably small inhibitor, CA-11. The 6-fluoro-5-amidinobenzimidzole, CA-11, is more than 1000-fold selective against natural Ala190 protease anti-targets, and more than 100-fold selective against other Ser190 anti-targets. [Copyright &y& Elsevier]

The rational design and synthesis of β-amino-α-hydroxy amide derivatives as reversible inhibitors of methionine aminopeptidase-2 (MetAP2) with anti-proliferative activity against human umbilical vein endothelial cells (HUVECs) is described. [Copyright &y& Elsevier]

An extensive structural manifold of short hydrogen bond-mediated, active site-directed, serine protease inhibition motifs is revealed in a set of over 300 crystal structures involving a large suite of small molecule inhibitors (2-(2-phenol)-indoles and 2-(2-phenol)-benzimidazoles) determined over a wide range of pH (3.5–11.4). The active site hydrogen-bonding mode was found to vary markedly with pH, with the steric and electronic properties of the inhibitor, and with the type of protease (trypsin, thrombin or urokinase type plasminogen activator (uPA)). The pH dependence of the active site hydrogen-bonding motif is often intricate, constituting a distinct fingerprint of each complex. Isosteric replacements or minor substitutions within the inhibitor that modulate the pKa of the phenol hydroxyl involved in short hydrogen bonding, or that affect steric interactions distal to the active site, can significantly shift the pH-dependent structural profile characteristic of the parent scaffold, or produce active site-binding motifs unique to the bound analog.Ionization equilibria at the active site associated with inhibitor binding are probed in a series of the protease–inhibitor complexes through analysis of the pH dependence of the structure and environment of the active site-binding groups involved in short hydrogen bond arrays. Structures determined at high pH (>11), suggest that the pKa of His57 is dramatically elevated, to a value as high as ∼11 in certain complexes. Ki values involving uPA and trypsin determined as a function of pH for a set of inhibitors show pronounced parabolic pH dependence, the pH for optimal inhibition governed by the pKa of the inhibitor phenol involved in short hydrogen bonds. Comparison of structures of trypsin, thrombin and uPA, each bound by the same inhibitor, highlights important structural variations in the S1 and active sites accessible for engineering notable selectivity into remarkably small molecules with low nanomolar Ki values. [Copyright &y& Elsevier]

Investigates the contribution of multicentered short hydrogen bond arrays to potency of active site-directed serine protease inhibitors. Variation in the length of active site hydrogen bonds; Evidence of minor effect on inhibitor potency; Production of large structural manifolds of active site hydrogen bond motifs.

The structure-based design of potent and selective urokinase-type plasminogen activator (uPA) inhibitors with 4-aminoarylamidine or 4-aminoarylguanidine S1 binding groups, is described. [Copyright &y& Elsevier]

GS-5734 is a monophosphate prodrug of an adenosine nucleoside analog that showed therapeutic efficacy in a non-human primate model of Ebola virus infection. It has been administered under compassionate use to two Ebola patients, both of whom survived, and is currently in Phase 2 clinical development for treatment of Ebola virus disease. Here we report the antiviral activities of GS-5734 and the parent nucleoside analog across multiple virus families, providing evidence to support new indications for this compound against human viruses of significant public health concern. [ABSTRACT FROM AUTHOR]

An one-pot reaction sequence is used for the preparation of tetrasubstituted cyclopentanes (V)/(VI). [ABSTRACT FROM AUTHOR]