A5067984811- Synthetic Organic Chemistry Methods
- Asymmetric Synthesis and Catalysis
- X-ray Diffraction in Crystallography
- Crystallization and Solubility Studies
- Fluorine in Organic Chemistry
- Chemical Synthesis and Reactions
- Microbial Natural Products and Biosynthesis
- Cyclopropane Reaction Mechanisms
- Chemical synthesis and alkaloids
- Cancer Treatment and Pharmacology
- Chemical Synthesis and Analysis
- Organic Chemistry Cycloaddition Reactions
- Steroid Chemistry and Biochemistry
- Oxidative Organic Chemistry Reactions
- Estrogen and related hormone effects
- Asymmetric Hydrogenation and Catalysis
- Sulfur-Based Synthesis Techniques
- Click Chemistry and Applications
- Synthesis of β-Lactam Compounds
- Carbohydrate Chemistry and Synthesis
- Synthesis and Catalytic Reactions
- Crystallography and molecular interactions
- Synthesis and Reactions of Organic Compounds
- Traditional and Medicinal Uses of Annonaceae
- Organoboron and organosilicon chemistry
Institute of Organic Chemistry
2008-2021
Polish Academy of Sciences
2009-2021
University of Warsaw
2017
National Veterinary Research Institute
1994-2007
University of Calgary
2002
The total diastereoselective synthesis of dicyclopenta[a,d]cyclooctane core skeleton tricyclic terpenoids, fusicoccins, and ophiobolins is reported. commences from 2-methylcyclopent-2-en-1-one leads first to the easily accessible intermediary cyclopenta[8]annulene 18. subsequent steps include two key transformations: shifting angular methyl group neighboring position employing a carbocationic rearrangement (26 → 28) construction quaternary stereogenic center via alkylation...
In the present work, validity of helicity rule relating absolute configuration bridgehead carbon atom in bicyclic β-lactams to sign 220 nm band observed their electronic circular dichroism (ECD) spectra is examined for ring-expanded cephalosporin analogues. To this end, a series model compounds with seven-membered ring condensed β-lactam unit was synthesized. A key step synthesis either ring-closing metathesis (RCM) or free radical cyclization leading an S, O, C at 6 position skeleton....
The first synthetic approach to the core structure of cardiac glycoside oleandrin exhibiting a potent cytotoxic activity, starting from common androstane derivative, has been accomplished. synthesis is focused on stereoselective transformations in densely substituted and sterically shielded five-membered ring (steroid D). developed paves route related bufadienolides, i.e., constituents traditional drug Ch'an Su, bufotalin, cinobufagin.
Abstract The first successful enantioselective hydrosilylation of cyclic imines promoted by a chiral zinc complex is reported. In situ generated zinc‐ProPhenol with silane afforded pharmaceutically relevant enantioenriched 2‐aryl‐substituted pyrrolidines in high yields and excellent enantioselectivities (up to 99% ee ). synthetic utility presented methodology demonstrated an efficient synthesis the corresponding amines, being pharmaceutical drug precursors Aticaprant Larotrectinib. magnified image
Sesqui- and sesterterpenes of ophiobolin fusicoccin families are important synthetic targets because complexity structure potentially useful physiological activities, including anti-tumor activity. A synthesis versatile building blocks for these terpenoids is described. Cyclopenta[8]annulene rings system with properly dislocated substituents was constructed using as key steps ring closing metathesis reaction Wagner - Meerwein rearrangement. Ring leading to cyclopenta[8]annulene studied in detail.
The origins of different stereoselectivities observed experimentally in the alkylations azulenone precursors guanacastepene A synthesis have been determined through density functional theory investigations. optimized transition structures methylation two show that steric effects, rather than torsional factors often determine such stereoselectivities, dictate preferred products observed.
An efficient and operationally simple synthesis of the neodolestane diterpenoids (±)-heptemerone G (±)-guanacastepene A is reported. The common tricyclic scaffold (±)-4 was prepared from 2-methylcyclopent-2-en-1-one via 23 isolated intermediates in 5.1% yield. key features include a novel annulation sequence combining tandem conjugate addition, methylenation, metathesis reaction completely diastereoselective transformation azulene derivative into rings AB building block 32. Stereochemistry...
Reactions of representative tosylhydrazones aldehydes and ketones with alpha-metalated sulfones were examined in order to develop a practical olefination method. Treatment aldehyde tosylhydrazone 2 an excess alpha-lithiated methyl phenyl or dimethyl yielded 3a. The reaction sterically unhindered lithiated alkyl gave mixtures the respective products 3b-d along Shapiro fragmentation product 4. Sterically hindered afforded exclusively. In contrast, 6 reactions variety alpha-magnesio primary...
New approaches to 25-hydroxy vitamin D building blocks 7 and 8 have been developed. Tandem acid-catalyzed conjugate addition of ketene acetal 2d or 2c acceptors 3 then 11 yielded 5b (76% from 3) 22 (64%), respectively, with the proper relative configuration on C20, C17, C13 (steroid numbering, all compounds are racemic). The trans-hydrindan ring junction in 16 27 has secured by chirality transfer palladium-catalyzed hydrogenolysis formates 15 26. Treatment N-bromoacetamide followed NaOH a...
An efficient synthesis of the key building block for 17-epi-calctriol from Hajos-Parrish dione involving a sequence diastereoselective transformation azulene core and side-chain construction is presented.
An enantioselective synthesis of the key bicyclic building block for (+)-heptemerone G and (+)-guanacastepene A construction has been accomplished. 2-Furyl methyl carbinol was used as starting material (<i>S</i>)-4-hydroxy-2-methylcyclopent-2-en-1-one primal optically active intermediate.
A series of representative optically active derivatives 4-hydroxy-5-alkylcyclopent-2-en-1-one were prepared from the respective 2-furyl methyl carbinols via Piancatelli rearrangement followed by enzymatic kinetic resolution racemates. Applicability chiroptical methods (experimental and calculated electronic circular dichroism [ECD] vibrational [VCD] spectra) to determine absolute configuration both stereogenic centers in 4-hydroxy-5-methylcyclopent-2-en-1-one was demonstrated. It also...
An efficient synthesis of 17-epi-calcitriol 2, an epimer natural hormone, via 17-epi-cholesterol 5a is described. Synthesis includes palladium-catalyzed cyclopropanation the common androstane derivative 7 with alkyl diazoacetate, reductive fission less shielded side cyclopropane carboxylic acid esters 6, oxidation products into 11a, and alkylation ester 11b. Photolysis 7,8-dedydro-17-epi-25-hydroxycholesterol 19b consecutive thermal rearrangement gave a mixture several that was subjected to...
Transformation of representative 2,3-epoxy alcohols, including 3-trimethylsilyl- and 3-triphenylsilylglycidols, into the corresponding 2,3-epithio alcohol dimethylthiocarbamate derivatives under mild alkaline conditions is reported.