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Introduction
The main focus of our effort is the research and development of novel metal-catalysed transformations as efficient and versatile synthetic methods. We have worked out intramolecular cyclisations of aminoalkenes - such as carbonylations, chlorinations and N,O-bicyclisations - as an alternative routes to polysubstituted piperidines. Particularly noteworthy is the discovery of Bi(OTf)3 promoted hydroamination of N-tosyl alkenyl amines to corresponding pyrrolidines under mild reaction conditions.
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Publications
Publications (43)
In order to expand the knowledge on linear alicyclic musks, a set of 29 small‐ring (racemic) analogues of the biodegradable and renewable alicyclic musk Romandolide was designed, prepared, and evaluated. The common short and modular synthesis employs either commercially available or easily accessible (substituted) cyclopropyl/cyclobutyl ketones and...
We have designed, prepared, and evaluated a set of racemic (un)saturated carba‐homologues of prominent musks Helvetolide and Serenolide. The short synthesis employs commercially available Artemone and/or Herbac, that are transformed in three steps to the target compounds. Their qualitative olfactory analysis revealed that incorporation of methylene...
Lilac aldehydes are considered as principal olfactory molecules of lilac flowers. We have designed, prepared, and evaluated a set of racemic seco-analogues of such natural products. The synthesis employs commercially available α-chloroketones as substrates that are transformed in four steps to target compounds. Their qualitative olfactory analysis...
A series of di‐/trinitroxide esters and amides featuring PROXYL and/or TEMPO radicals connected with alicyclic bridges were prepared in 61–92 % yields and their properties were analysed by using multiple experimental techniques. The examination of EPR spectra of radicals in organic solvents augmented with DFT calculations brought valuable informati...
The advantageous properties of ethylene glycol diacetate (EGDA) qualify it as a
useful substitute for glycerol triacetate (GTA) for various green applications. We scrutinised the
lipase-mediated acetylation of structurally diverse alcohols in neat EGDA furnishing the range of
naturally occurring fragrant acetates. We found that such enzymatic syste...
(S)-5-Methylhept-2-en-4-one is a key flavour compound in hazelnuts. We have performed its chiral-pool-based chemoenzymatic synthesis with 39% overall yield (73% ee). The four-step aldol-based sequence avoids the use of highly reactive and/or toxic reagents, does not require anhydrous conditions and uses only distillation as the purification method....
The reaction of tosylated 2-alkoxypyrazines with potassium halides led to the unexpected formation of N-alkylated pyrazinones. Such rare example of substitutive C–O → C–N rearrangement on pyrazines was then scrutinised by using various nucleophiles to afford the respective products in moderate to good yields. This method provides a direct access to...
The comprehensive review of filbertone, a principal flavour compound of hazelnut, evaluates the current state-of-the-art of all relevant aspects of the title molecule: its occurrence and properties, laboratory preparation and bulk synthesis, analytical issues regarding stereochemistry and purity, sensory evaluation and practical uses. Comparison is...
Matching of competitor flavours is one of the most common tasks for the majority of flavour chemists working for a flavour house. It is obvious to find various artefacts in those flavourings, where carbonyl compounds, alcohols and acids are together part of the recipe. Unfortunately, mass spectra of many of these compounds are not available in the...
A series of polynitroxide amides possessing PROXYL and/or TEMPO units connected with various bridges were synthesized and their properties were analyzed using multiple experimental techniques. EPR spectroscopy provided a detailed insight into their paramagnetic character and related properties. The thorough examination of EPR spectra of dinitroxide...
The unexpected formation of previously non-described semi/conjugated ethyl trienoate revealed its powerful aroma of fresh pineapple. Thus, we have designed, prepared and evaluated a set of its carbonyl analogues as mixtures of (E/Z)-isomers. While their synthesis from natural ocimene led to target compounds in low yields, optimised preparation from...
The stereoselective palladium-catalysed cyclocarbonylation of hex-5-ene-1,4-diols affords cis-fused bicyclic lactones only. Ring-opening with N,O-dimethylhydroxylamine hydrochloride gives the corresponding Weinreb amides, and their subsequent recyclisation provides advanced synthons for the prospective synthesis of decarestrictine L. The relative c...
A two comparative sets of mono-/dinitroxyl amides were designed and prepared. The novel TEMPO and/or PROXYL derivatives were fully characterised and their spin, redox and antimicrobial properties were determined. Cyclic voltammetry revealed (quasi)reversible redox behavior for most of the studied radicals. Moreover, the electron-withdrawing substit...
A comparison set of mono-/biradical TEMPO derivatives was prepared, novel compounds were fully characterized, and their physicochemical properties were determined. Cyclic voltammetry revealed reversible redox behavior for all studied nitroxides. Moreover, the electron-withdrawing substituents increased the oxidation potential of the respective nitr...
The stereospecific Pd/Cu-catalysed oxycarbonylation of syn/anti-hex-5-ene-2,4-diols 7/8 was used as
a key step in the synthesis of bicyclic lactones 5 and 6. Eventually, the major intermediate 5 was
transformed to the bis-tetrahydrofuran subunit of naturally occurring diterpenoid (-)-neopallavicinin 2.
The target compound 3E was thus prepared in 7....
The two-part critical review deals with the metal-catalyzed intramolecular hydroaminations of
alkenyl amines having terminal double bond. Following the first part, this second one summarizes the
employment of known hydroamination catalysts based on various transition metals in the direct preparation
of pyrrolidines and piperidines. The focus is giv...
The two-part critical review deals with the metal-catalyzed intramolecular hydroaminations of alkenyl amines having terminal double bond. In this first part, the description of the hydroamination as well as the substrate activation via Thorpe-Ingold effect and/or gem-dialkyl/aryl-substitution is presented at the beginning. The main body summarizes...
Bi(OTf)(3)·nH(2)O was found to be an efficient promoter of the cyclisative hydroamination of unactivated alkenyl sulfonamides, giving rise to the N-protected 2-methyl pyrrolidines in good to excellent yields (up to 95%). Based on control experiments, a joint Lewis acid-Brønsted acid catalysis might be in operation, or triflic acid itself, generated...
The 2,6-disubstituted piperidine alkaloids (+)-dihydropinidine
(1), (-)-epidihydropinidine (2) (as HCl salts), and (-)-
pinidinone (3) were efficiently synthesized from (S)-epichlorohydrin
(7) as common substrate using regioselective Wacker-Tsuji oxidation
of alkenylazides 10 and 14 as well as a highly diastereoselective
reduction of cyclic imine 1...
The diastereoselective PdCl2/CuCl2-catalysed intramolecular methoxyaminocarbonylation of N-benzyl
protected alkenyl amine 4 was used as a key step in the total synthesis of the naturally occurring piperidine
alkaloid (�)-pinidinone. Commercially available (S)-propylene oxide was employed as starting
material, delivering the key substrate 4 in three...
ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
Optically pure (þ)-calvine, (þ)-2-epicalvine, (2S,6S)-(6-pentylpiperidin-2-yl)acetic acid methyl ester and
(2R,6S)-(6-pentylpiperidin-2-yl)acetic acid methyl ester, four piperidine alkaloids isolated from ladybird
beetles of the genus Calvia (Coccinellidae), were synthesised from a common precursor using cyclisative
Pd(II)/Cu(II)-catalysed carboami...
ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
The intramolecular Pd(II)-catalysed carbonylation of aminoalkenitol was used as a key step in the short racemic syntheses of the ladybird beetle alkaloids calvine and epicalvine. The title compounds have been prepared in 26% overall yield over four steps starting from hexanal and pentenyl bromide.
The total synthesis of two novel l-ido and l-altro configured 6-chloro-1,5,6-trideoxyiminohexitols featuring a highly diastereoselective Pd(II)/CuCl2-catalysed chlorocyclisation of sugar-derived aminoalkenitols has been accomplished. The requisite substrates were, in turn, prepared from chiral pool materials starting from the cheap and commercially...
Novel type of Pd(II)-catalysed transformation of sugar-derived alkenitols furnishing 7-benzyloxy-2,5-dioxabicyclo[2.2.1]heptanes was discovered. The investigated bicyclisation displays an exceptional substrate selectivity towards xylo-configured unsaturated polyols. Moreover, a newly build stereogenic centre is formed in a diastereospecific cis-man...
Novel type of Pd(II)-catalysed transformation of sugar-derived alkenitols furnishing 7-benzyloxy-2,5-dioxabicyclo[2.2.1]heptanes was discovered. The investigated bicyclisation displays an exceptional substrate selectivity towards xylo-configured unsaturated polyols. Moreover, a newly build stereogenic centre is formed in a diastereospecific cis-man...
1-(Benzyloxycarbonylamino)-hex-5-en-3-ol undergoes a novel Pd(II)/CuCl2-catalysed bicyclisation to furnish the corresponding 6-oxa-2-azabicyclo[3.2.1]octane in good yield.
The synthesis of C-mannosyl-guanosine 23, an advanced intermediate for the preparation of stable
analogues of guanofosfocin, is described. This convergent approach features an improved Traube-type synthesis of a 8-substituted guanine, followed by ribosylation. NMR Studies show that the C-mannopyranosyl moiety of 23 adopts a distorted 1C4 conformati...
The ®rst successful Pd(II)-catalysed aminocarbonylation of the highly substituted benzylaminoalkene 5
allows the direct preparation of fused piperidine lactones 3 and 4, which are subsequently converted to the
novel C-6 homologue of 1-deoxynojirimycin 1 and 1-deoxy-l-idonojirimycin 2. The study of the in¯uence
of various catalytic conditions on the...
The absolute configuration at the new stereogenic centre during the key step of the total synthesis was established byX-ray analysis of the title compound, C7H15NO4⁺·Cl⁻.
Novel piperidine lactones 1 and 2, which represent direct precursors to the new C-6 homologues of 1-deoxynojirimycin (3) and 1-deoxy-L-idonojirimycin 4, were prepared by key Pd(II)-catalysed aminocarbonylation of protected aminoalkene 10.
(R)-4-Phenyl-5,5-dimethyl-oxazolidin-2-one, readily available from D-phenylglycine, is shown to be an effective chiral auxiliary for stereoselective conjugate additions to attached a,d-unsaturated N-acyl moieties. Its utility is demonstrated by the asymmetric synthesis of the antifungal, antibacterial (-)-Aplysillamide B.
The first total synthesis of erythroskyrine, a polyenoyltetramic acid mycotoxin and principal pigment of Penicillium Islandicum Sopp., is described using a palladium(II) catalysed oxycarbonylation to create the furan-derived bicyclic portion 3 and the phosphonate ester 5 to furnish both the polyenoyl chain and the N-methyl (S)-valine derived tetram...
The general approach to optically active anhydroalditols, a class of compounds that have proven most
versatile intermediates for C-nucleosides / C-glycosides syntheses is presented. Our entry into this field
features the palladium(II)-catalyzed oxycarbonylation of unprotected enitols as key step.
The total syntheses of some natural styryl-lactones...