Abstract The first aminocatalyzed α‐alkylation of α‐branched aldehydes with benzyl bromides as alkylating agents has been developed. Using a sterically demanding proline derived catalyst, racemic are reacted in DYKAT process to give the corresponding α‐alkylated quaternary stereogenic centers good yields and high enantioselectivities.

Abstract A conformationally restricted monofluorinated α‐amino acid, (3‐fluorobicyclo[1.1.1]pentyl)glycine (F‐Bpg), was designed as a label for the structural analysis of membrane‐bound peptides by solid‐state 19 F NMR spectroscopy. The compound synthesized and validated replacing natural aliphatic acids. Calculations suggested that F‐Bpg is similar to Leu/Ile in terms size lipophilicity. incorporated into membrane‐active antimicrobial peptide PGLa provided information on structure lipid bilayer.

The synthesis of 3-azabicyclo[3.2.0]heptyl boropinacolates and trifluoroborates via the [2 + 2] photocycloaddition corresponding alkenyl boronic derivatives maleimides or maleic anhydride is described. Optimization reaction conditions (i.e., wavelength, concentration reagents, photosensitizer) was carried out, scope limitations method were studied. Alkenyl acid pinacolates found to be more suitable for cycloaddition, providing better outcomes compared trifluoroborates. utility this approach...

The literature on cycloaddition reactions of boron-containing alkenes is surveyed with 132 references. data are categorized according to the reaction type ([2+1], [2+2], [3+2], [4+2], and [4+3] cycloadditions). cyclopropanation Diels–Alder alkenylboronic derivatives have been studied more or less comprehensively, for some substrates, they can be considered as convenient methods rapid regio- stereoselective construction even complex cyclic systems. Other types cycloadditions, well mechanistic...

Abstract Die erste aminokatalytische α‐Alkylierung α‐verzweigter Aldehyde mit Benzylbromiden als Alkylierungsmittel wurde entwickelt. Unter Verwendung eines sterisch anspruchsvollen, von Prolin abgeleiteten Katalysators reagieren racemische α‐verzweigte Alkylierungsmitteln in einem DYKAT‐Prozess und ergeben guten Ausbeuten hohen Enantioselektivitäten α‐alkylierte quartären Stereozentren.

Preparation of 2,2‐disubstituted and 2‐monosubstituted alkenylboronic acid esters from aliphatic aromatic ketones aldehydes by the boron‐Wittig olefination with bis[(pinacolato)boryl]methane was examined applied on multigram scale. The influence substrate steric electronic features overall efficiency stereochemical outcome reaction studied. Additionally, a series diversely functionalized (hetera)cycloalkylidenemethyl (hetera)cycloalkyl boronic acid‐derived building blocks synthesized.

Syntheses of bicyclo[1.1.1]pentane‐derived azides and terminal alkynes – interesting substrates for click reactions are described. With a few exceptions, these compounds were prepared in two or three steps starting from common synthetic intermediates the corresponding carboxylic acids. The key step synthesis 1‐azidobicyclo[1.1.1]pentanes is copper‐catalysed diazo‐transfer reaction with imidazole‐1‐sulfonyl azide. preparation bicyclo[1.1.1]pentyl‐substituted relies on Seyferth–Gilbert...

Difluorocyclopropanation of alkenyl trifluoroborates using TMSCF 3 –NaI system was reported for the first time. The developed method allowed preparation monocyclic, spiro‐ and fused‐bicyclic gem ‐difluorocyclopropanes bearing additional functional groups. potassium (2,2‐difluorocyclopropyl)trifluoroborates achieved in up to 90 % yield on a multigram scale.

A conformationally restricted monofluorinated α-amino acid, (3-fluorobicyclo[1.1.1]pentyl)glycine (F-Bpg), was designed as a label for the structural analysis of membrane-bound peptides by solid-state 19F NMR spectroscopy. The compound synthesized and validated replacing natural aliphatic acids. Calculations suggested that F-Bpg is similar to Leu/Ile in terms size lipophilicity. incorporated into membrane-active antimicrobial peptide PGLa provided information on structure lipid bilayer.

A convenient approach to 1,3‐bifunctional sulfonyl fluorides, sulfonamides and sulfinates bearing a bicyclo[1.1.1]pentane unit attached the sulfur atom (protected) amino or carboxyl group is described. The method relied on photochemical decomposition of Barton [1‐hydroxypyridine‐2(1 H )‐thione] esters corresponding carboxylic acids as key step, followed by oxidation cleavage 2‐pyridyl moiety. title building blocks were obtained gram scale, their utility was demonstrated preparation an...

Facile synthesis of 5-fluoropyrazoles by direct fluorination pyrazoles with N-fluorobenzenesulfonimide (NFSI) was elaborated. This approach used to prepare the unsubstituted 5-fluoro-1 H-pyrazole, known fungicide Penflufen, and many functionalized 5-fluoropyrazoles: building blocks for medicinal chemistry agrochemistry.

Abstract A convenient approach to the multigram synthesis of functionalized 1,2‐disubstituted cyclopropyltrifluoroborates was developed, based on Pd(II)‐ or Cu(I)‐catalyzed reaction vinyltrifluoroborate and diazo compounds. Optimized protocols allowed for preparation target products as pure diastereomers scale. It shown that title compounds were good coupling partners Suzuki‐Miyaura Chan‐Lam reactions, which provide medicinally relevant (het)arylcyclopropanes with high diastereoselectivity....

An approach to the synthesis of oxa‐ and azabicyclo[ n .1.0]alkan‐1‐yl trifluoroborates on a multigram scale was developed. Two synthetic strategies were evaluated: first based lithiation–borylation corresponding 2‐bromoallyl derivatives, other relying regioselective hydroboration appropriate hetera‐substituted enynes. The second method appeared be more efficient in terms scalability substrate scope. Further steps included ring closing‐metathesis, mild palladium‐catalyzed cyclopropanation...

Differentiation of identical electrophilic functional groups (carboxylates) by a strategically placed internal nucleophile (an amino group) in cyclic precursors was used as key general approach to functionalized azabicyclic scaffolds.

An approach to the synthesis of 1-alkyl-5-((di)alkylamino)tetrazoles by nucleophilic substitution in 1-alkyl-5-sulfonyltetrazoles with anions generated from primary or secondary amines was developed. Tolerance method presence some functional groups (i.e., protected amine) both components reaction demonstrated. Obtained tetrazoles are promising building blocks for design peptide surrogates, particular, replacement approaches alkyl urea derivatives.

The coordination polymers with<italic>trans</italic>-(<italic>S</italic>,<italic>S</italic>)-1,2-cyclopropane dicarboxylate or (1<italic>R</italic>,3<italic>S</italic>)-camphorate contain only one polar group in close proximity to the asymmetric C atom but show different sorption of (<italic>R</italic>) (<italic>S</italic>) isomers 2-butanol.

The synthesis of optically pure (1<i>S</i>,4<i>S</i>)-2,5-diazabicyclo[2.2.1]heptane-1-carboxylic acid starting from easily available 'chiral pool' <sc>l</sc>-4-hydroxyproline is reported. A tandem Strecker reaction–intramolecular nucleophilic cyclization (STRINC) sequence was used as the key synthetic step for first time to prepare a diamino acid. Careful examination side products obtained in STRINC allowed suggestion mechanistic explanation observed facts and optimization yield...

A scalable synthesis was developed of 3,5-methanoni­pecotic acid (3-azabicyclo[3.1.1]heptane-1-carboxylic acid), a rare example conformationally constrained nonchiral β-amino acid, potentially useful in peptide engineering and peptidomimetic drug design. retrosynthetic strategy based on disconnections exclusively within the symmetry planes target intermediate molecules found to be might deliver expedite syntheses other similar cases.

An approach to 2-azabicyclo[n.2.0]alkane derivatives (n = 1, 2), which relies on a tandem Strecker reaction–intramolecular nucleophilic cyclization (STRINC) sequence of the corresponding 2-(ω-chloroalkyl)cyclobutanones (in turn prepared by [2+2] cycloaddition keteniminium salts and ethylene) is described. The utility method demonstrated multigram syntheses bicyclic proline analogues, monoprotected diamines, as well parent 2-azabicyclo[4.2.0]octane.