One-step chemoselective conversion of tetrahydropyranyl ethers to silyl-protected alcohols

RSC Advances ◽  
2014 ◽  
Vol 4 (28) ◽  
pp. 14475-14479 ◽  
Author(s):  
Julián Bergueiro ◽  
Javier Montenegro ◽  
Carlos Saá ◽  
Susana López

A novel chemoselective one-pot transformation of acetals to silyl ethers is reported. Free hydroxyls, double bonds and triple bonds are unaffected in optimal reaction conditions. This practical, inexpensive protocol allows the selective replacement of acetal-forming protecting groups with silyl groups in a single step under mild conditions.

2016 ◽  
Vol 12 ◽  
pp. 1772-1777 ◽  
Author(s):  
Lena Huck ◽  
Juan F González ◽  
Elena de la Cuesta ◽  
J Carlos Menéndez

A sequential three-component process is described, starting from 3-arylmethylene-2,5-piperazinediones and involving a one-pot sequence of reactions achieving regioselective opening of the 2,5-diketopiperazine ring and diastereoselective generation of an aziridine ring. This method allows the preparation of N-unprotected, trisubstituted aziridines bearing a peptide side chain under mild conditions. Their transformation into β-trifluoroacetamido-α-ketoamide and α,β-diketoamide frameworks was also achieved in a single step.


2013 ◽  
Vol 37 (1) ◽  
pp. 25-27 ◽  
Author(s):  
Maaroof Zarei

Cyanuric fluoride works as an efficient acid activator reagent for the direct [2+2] ketene–imine cycloaddition of substituted acetic acids and imines in a one-pot synthesis under mild conditions. The yields are good to excellent and the reaction conditions are mild, simple and efficient.


Synthesis ◽  
2019 ◽  
Vol 51 (07) ◽  
pp. 1585-1594 ◽  
Author(s):  
Lailai Wang ◽  
Zhiwen Zheng

A new efficient catalytic system for one-step synthesis of N-arylated amines, for example, an important intermediate, 4-ethyl-N-[(tetrahydrofuran-3-yl)methyl]aniline, is achieved by using different rhodium precursor and phosphorus ligands catalyzed hydroaminomethylation of aniline and its derivatives with heterocyclic and/or cyclic olefins. By screening the reaction parameters, the optimal reaction conditions are found as follows: methanol as a solvent, PPh3 as a ligand, [Rh(cod)2]BF4 as a catalyst precursor, a P/Rh ratio of 5:1, syngas pressure 4 MPa (H2/CO = 3:1), 100 °C, 20 hours, and no additives. The conversion of aniline reaches >99% and the yield of N-[(tetrahydrofuran-3-yl)methyl]aniline is up to 99% using this catalytic system. Moreover, the reaction of aniline and various cyclic olefins is investigated under the optimal conditions, and excellent conversion and good yields are obtained.


Synlett ◽  
2017 ◽  
Vol 28 (19) ◽  
pp. 2675-2679 ◽  
Author(s):  
Chenghui Sun ◽  
Honggang Liang ◽  
Lingxiang Bao ◽  
Yao Du ◽  
Yiying Zhang ◽  
...  

Cyanamides were selectively formed through a one-step nucleophilic substitution reaction of allylic tertiary amines with cyanogen bromide. Because of the mild reaction conditions and good yields of the reaction, as well as the commercial availability of the starting materials, this new method represents a valuable tool for the synthesis of cyan­amides through an N-deallylation reaction and an N-cyanation reaction in one pot.


Synlett ◽  
2019 ◽  
Vol 30 (12) ◽  
pp. 1437-1441
Author(s):  
Xu yan Cao ◽  
Fei Huang ◽  
Songlin Zhang

The first example of carbon double-bond formation via praseodymium-mediated Barbier type reaction of ketones and allyl halides in the presence of diethyl phosphite is reported. The reaction is highly α-regioselective and conveniently carried out under mild conditions in a one-pot fashion. From a synthetic point of view, a series of conjugated alkenes were obtained in moderate to good yields in this one-pot reaction with practical reaction conditions.


Synthesis ◽  
2020 ◽  
Vol 52 (22) ◽  
pp. 3446-3451
Author(s):  
Songlin Zhang ◽  
Dengbing Xie ◽  
Yiqiong Wang ◽  
Bo Yang

The carbon–carbon double bond formation via neodymium-mediated Barbier-type reaction of ketones and allyl halides in the presence of diethyl phosphite is reported for the first time. The reaction is highly α-regioselective and was conveniently carried out under mild conditions in a one-pot fashion. From a synthetic point of view, a series of conjugated alkenes were obtained in moderate to good yields in this one-pot reaction with feasible reaction conditions.


Synlett ◽  
2018 ◽  
Vol 29 (05) ◽  
pp. 668-672 ◽  
Author(s):  
Jianbo Zhang ◽  
Guosheng Sun ◽  
Yue Wu ◽  
Anqi Liu ◽  
Saifeng Qiu ◽  
...  

Glycosides as glycosyl donors using FeCl3 have been described. Under optimal reaction conditions, three kinds of propargyl glycosides were found to react with steroids and sugar-derived glycosyl acceptors to afford the corresponding disaccharides and glycoconjugates in good to excellent yields (66–91%). Meanwhile, the method can also realize one-pot synthesis of disaccharides, making it an effective, affordable, and green glycosylation procedure.


2013 ◽  
Vol 661 ◽  
pp. 47-52
Author(s):  
Gang Chen ◽  
Chun Hua Yang

Gold nanoparticles (AuNPs) were attached to the surface of alumina particles by an in-situ immobilizing method. SEM and XPS analysis showed that the coverage of alumina particles by AuNPs increased as the amount of alumina decreased; AuNPs onto alumina particles by the conventional colloidal deposition method were also prepared, whose TEM showed that the coverage of AuNPs was evidently smaller than that in the case of modified colloidal deposition method,although the AuNPs were spread almost uniformly over the surface of alumina particles. Au-immobilized alumina particles were subsequently utilized as the catalysts for direct amination of benzene with NH3H2O as an aminating agent and H2O2 as an oxidant under mild conditions. The reaction conditions were optimized: when catalyst amount was 2.0 g, reaction temperature was 50 °C, NH3H2O amount was 60 mL, H2O2 amount was 30 mL, and reaction time is 2 h, Au-immobilized alumina particles showed the highest aniline yield (1.96 mg) for 25 mL benzene.


2020 ◽  
Author(s):  
Cheng Li-Jie ◽  
Zhao Siling ◽  
Neal Mankad

A Cu-catalyzed carbonylative borylation of unactivated alkyl halides has been developed, enabling efficient synthesis of aliphatic potassium acyltrifluoroborates (KATs) in high yields by treating the in-situ formed tetracoordinated acylboron intermediates with aqueous KHF2. A variety of functional groups are tolerated under the mild reaction conditions, and primary, secondary and tertiary alkyl halides are all applicable. In addition, this method also provides facile access to N-methyliminodiacetyl (MIDA) acylboronates as well as α-methylated potassium acyltrifluoroborates in a one-pot manner. Mechanistic studies indicate a radical atom transfer carbonylation (ATC) mechanism to form acyl halide intermediates that are subsequently borylated by (NHC)CuBpin.<br>


2015 ◽  
Vol 11 ◽  
pp. 66-73 ◽  
Author(s):  
Bianca Rossi ◽  
Nadia Pastori ◽  
Simona Prosperini ◽  
Carlo Punta

Following an optimized multicomponent procedure, an aryl amine, a ketone, and a cyclic ether or an alcohol molecule are assembled in a one-pot synthesis by nucleophilic radical addition of ketyl radicals to ketimines generated in situ. The reaction occurs under mild conditions by mediation of the TiCl4/Zn/t-BuOOH system, leading to the formation of quaternary β-amino-ethers and -alcohols. The new reaction conditions guarantee good selectivity by preventing the formation of secondary products. The secondary products are possibly derived from a competitive domino reaction, which involves further oxidation of the ketyl radicals.


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