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We report an efficient method to prepare polysubstituted 3-hydroxypyridines from amino acids, propargyl alcohols, and arylboronic acids. The process involves Pd(0)-catalyzed anti-selective arylative cyclizations of N-propargyl-N-tosyl-aminoaldehydes with arylboronic acids (“anti-Wacker”-type cyclization), oxidation of the resulting 5-substituted-3-hydroxy-1,2,3,6-tetrahydropyridines to 3-oxo derivatives, and elimination of p-toluenesulfinic acid. This method provides diverse polysubstituted 3-hydroxypyridines, whose hydroxy group can be further substituted by a cross-coupling reaction via a triflate.

Catalytic oxidation reactions often suffer from drawbacks such as low yields and poor selectivity. Particularly, selective oxidation of alcohols becomes more difficult when a compound contains more than one oxidizable functional group. In order to deliver a methodology that addresses these issues, herein we report an efficient, aerobic, chemoselective and simplified approach to oxidize a broad range of benzyl and propargyl alcohols containing diverse functional groups to their corresponding aldehydes and ketones in excellent yields under mild reaction conditions. Optimal yields were obtained at room temperature using 1 mmol substrate, 10 mol % copper(I) iodide, 10 mol % 4‐dimethylaminopyridine (DMAP), and 1 mol % 2,2,6,6‐tetramethylpiperidine 1‐oxyl (TEMPO) in acetonitrile, under an oxygen balloon. The catalytic system can be applied even when sensitive and oxidizable groups such as alkynes, amines, and phenols are present; starting materials and products containing such groups were found to be stable under the developed conditions. Chemoselective alcohol oxidation! Catalytic oxidation reactions often suffer from low yields and selectivity. Here we develop a method using copper(I) catalysts to selectively oxidize a wide range of benzyl and propargyl alcohols to their corresponding aldehydes and ketones under mild reaction conditions and with excellent yields. This chemoselective catalytic oxidation scheme can tolerate even sensitive and oxidizable groups such as alkynes, amines, and phenols.

Enantioselective α -aminomethylation of carbonyl compounds constitutes a powerful protocol for introducing aminomethyl groups to simple organic molecules. However, current strategies rely on nucleophile-based enantioselective activation with inherently activated substrates only, and enantioselective protocol based on the activation of in situ-generated unstable formaldimines remains elusive, probably owing to their unstable nature and the lack of steric environment for efficient stereocontrols. Here, based on a rhodium/chiral phosphoric acid cooperative catalysis, we achieved an enantioselective three-component reaction of α -diazo ketones with alcohols and 1,3,5-triazines. A dual hydrogen bonding between the chiral phosphoric acid catalyst and two distinct active intermediates was proposed to be crucial for the efficient electrophile-based enantiocontrol. A series of chiral β -amino- α -hydroxy ketones including those derived from simple aliphatic alcohols, allylic alcohol, propargyl alcohol, complicated natural alcohols and water could all be prepared in high efficiency and enantioselectivity. Strategies for enantioselective α -aminomethylation of carbonyl compounds rely on the chiral activation of stable ketones substrate. Here, the authors report a rhodium/chiral phosphoric acid cooperative catalysis for the three-component reaction of α -diazo ketones with alcohols and 1,3,5-triazines via imine chiral activation.

Propargyl alcohol is a useful synthon in synthetic organic chemistry. We found that the ruthenium(II) complex [Cp*RuCl(diene)] (Cp* = η5-C5Me5; diene = isoprene or 1,5-cyclooctadiene (cod)) catalyzes dimerization of 1,1-diphenylprop-2-yn-1-ol (1,1-diphenylpropargyl alcohol, 1a) at room temperature to afford an alkylidenebenzocyclobutenyl alcohol 2a quantitatively. Meanwhile, a stoichiometric reaction of the related hydrido complex [Cp*RuH(cod)] with 1a at 50 °C led to isolation of a ruthenocene derivative 4 bearing a cyclopentadienyl ring generated by dehydrogenative trimerization of 1a. Detailed structures of 2a and 4 were determined by X-ray crystallography. The reaction mechanisms for the formation of 2a and 4 were proposed.

Sigmatropic rearrangement provides a versatile strategy to site-selectively reorganize carbon-skeleton with high atom- and step-economy. Herein, we disclose a Mn(I)-catalyzed sigmatropic rearrangement of β, γ-unsaturated alcohols via C-C σ bond activation. A variety of α-aryl-allylic alcohols and α-aryl-propargyl alcohols could undergo in-situ 1,2- or 1,3- sigmatropic rearrangements to allow for converting to complex structural arylethyl- and arylvinyl- carbonyl compounds under a simple catalytic system. More importantly, this catalysis model can be further applied to assemble macrocyclic ketones through bimolecular [2n + 4] coupling-cyclization and monomolecular [n + 1] ring-extension. The presented skeleton rearrangement would be a useful tool complementary to the traditional molecular rearrangement. Molecular rearrangements are ubiquitous in modern synthetic chemistry, providing a powerful strategy to arrive at complex structures in an atom- and step-economic process. Here, the authors disclose a Mn(I)- catalyzed sigmatropic rearrangement of β, γ-unsaturated alcohols via C-C σ-bond activation to site-selectively reorganize carbon skeletons.

The transformation and utilization of amides are significant in organic synthesis and drug discovery. Here we demonstrate a divergent alkynylative difunctionalization of amides in a single transformation. In this reaction, amides react with an organometallic nucleophile to form a tetrahedral intermediate. By altering the N -substitution or the acyl group, the tetrahedral intermediate species selectively undergoes C–O or C–N cleavage with a concomitant capture by an alkynyl nucleophile generated in situ. This process enables the selective introduction of two different functional groups into the amide molecular architecture, producing valuable propargyl amine and propargyl alcohol products. The selectivity between deoxygenation and deamination process has been further elucidated by DFT calculations. Overall, this reaction successfully transforms the traditional mode of nucleophilic acyl addition to amides to a divergent C–O/C–N cleavage. The particularly wide substrate scope, including late-stage modification of bioactive molecules, demonstrates its potential broad applications in organic synthesis. The development of methods for conversion and utilization of amides has attracted much attention in organic synthesis and drug discovery. Herein, the authors report a divergent alkynylative difunctionalization of amides in a single transformation to generate either amines or alcohols through C–O or C–N cleavage.

A triode derivative of propargyl alcohol has been synthesized, and the effects of catalyst concentration, time and temperature on the synthesis process have been studied. Various concentrations of alkalis (5,0–30,0 mass. %) have been used as catalysts. It has been found that 2,3,3–triode propene–2–ol–1 has a higher yield when the concentration of the catalyst NaOH is 15%. The effect of time duration (1–5 hours) on product productivity has also been studied. Product yield has been found to be high for 3 hours. In addition, the effect of temperature on the product’s productivity has also been studied at intervals of (10–60°C). It has been found that the yield of 2,3,3–triiodpropen–2–ol–1 was high in 3 hours at 20°C. The structure of the synthesized substance was studied and confirmed by the methods of IR– and NMR–spectroscopic analysis.

A series of new thermosetting diimides containing terminal propargyl groups was synthesized via one-step high-temperature catalytic condensation of dianhydrides of a tetracarboxylic acid with N -Boc-(4-propargyloxy)aniline (APR) in the so-called “active medium”, viz. molten benzoic acid. Structures of the obtained compounds were confirmed by 1 H NMR and IR spectroscopy. The effect of symmetrical and unsymmetrical structures of the middle bis-imide moiety obtained from dianhydrides of isomeric diphenyltetracarboxylic acid on physicochemical characteristics of the diimides was evaluated. A similar comparison of properties was also carried out for a pair of new propargyl-containing diimides synthesized from dianhydrides of symmetric and asymmetric structure: 4,4-biphenylenedioxydiphthalic and 3,4-biphenylenedioxydiphthalic dianhydrides, respectively. Thermal properties of thermosetting oligoimides were estimated using DSC and TMA methods. It was found that their thermal properties and solubility in organic solvents depend significantly on the structure of central bis-imide moiety.

The synthesis of poly(4-vinylbenzyl-g- β -butyrolactone) (poly(VB-g-BL)) graft copolymer was carried out by “click” chemistry of terminal azido poly(4-vinylbenzyl chloride) (PVB-N 3 ) and terminal propargyl poly( β -butyrolactone) ( β -BL-propargyl). For this purpose, poly(4-vinylbenzyl chloride) (poly-4-VBC) was obtained using 4-vinylbenzyl chloride and 2,2′-azobis(2-methylpropionitrile) by free-radical polymerization. PVB-N 3 was synthesized using sodium azide and poly-4-VBC. β -BL-propargyl was obtained by the reaction of β -butyrolactone monomer with propargyl alcohol via ring-opening polymerization. The graft copolymer was also synthesized via “click” chemistry, employing PVB-N 3 and β -BL-propargyl. The products were thoroughly characterized by GPC, FT-IR, SEM, and 1 H-NMR. DSC and TGA were used to track the graft copolymer’s thermal characteristics. Thermal and spectroscopic measurements verified that the reactions were effectively completed. Graphical abstract Poly(4-vinylbenzyl chloride) was obtained by free-radical polymerization. Terminal azido poly(4-vinylbenzyl chloride) was synthesized using sodium azide and poly(4-vinylbenzyl chloride). Terminal propargyl poly(β-butyrolactone) was obtained by β-butyrolactone and propargyl alcohol via ring-opening polymerization. Poly(4-vinylbenzyl-g-β-butyrolactone) graft copolymer was synthesized by “click” chemistry. Thermal and spectroscopic measurements verified that the reactions were completed.

A series of 21 novel compounds based on noscapine were synthesized and investigated as potential anticancer therapeutics. These new compounds were prepared from the N -demethylation of noscapine followed by the three-component A 3 -coupling of N -nornoscapine as a secondary amine, an aldehyde and a terminal alkyne catalyzed by copper iodide (CuI). Two classes of derivatives were synthesized by applying phenylacetylene and propargyl alcohol as the alkyne moiety. Chemical structures of the products were confirmed by 1 HNMR, 13 CNMR, and HR-MS. In vitro cytotoxicity of the synthesized derivatives was studied on MCF-7 breast cancer cell line treated with different doses of compounds for 48 h. Compounds 6l , 6n and 6h ( IC 50  = 18.94, 19.29 and 32.11 µM, respectively) displayed the highest potency compared to that of noscapine (IC 50  = 36.38 µM).