3906-07-8Relevant articles and documents
Palladium-Catalyzed Synthesis of α-Methyl Ketones from Allylic Alcohols and Methanol
Biswal, Priyabrata,Samser, Shaikh,Meher, Sushanta Kumar,Chandrasekhar, Vadapalli,Venkatasubbaiah, Krishnan
, p. 413 - 419 (2021/11/01)
One-pot synthesis of α-methyl ketones starting from 1,3-diaryl propenols or 1-aryl propenols and methanol as a C1 source is demonstrated. This one-pot isomerization-methylation is catalyzed by commercially available Pd(OAc)2 with H2O as the only by-product. Mechanistic studies and deuterium labelling experiments indicate the involvement of isomerization of allyl alcohol followed by methylation through a hydrogen-borrowing pathway in these isomerization-methylation reactions.
Facile microwave-assisted synthesis and antitubercular evaluation of novel aziridine derivatives
Sarojini, Perumal,Jeyachandran, Malaichamy,Sriram, Dharmarajan,Ranganathan, Palraj,Gandhimathi
, (2021/02/26)
Novel 2-(aryloxymethyl)aziridines and 2-((3-aryl-1-phenylallyloxy)methyl)aziridine derivatives were prepared via ring-opening reaction of epoxides. The synthesized derivatives were characterized by using elemental analysis (EA), FT-IR, 13C NMR, and 1H NMR. The in vitro antitubercular activities of the synthesized compounds were evaluated against Mycobacterium tuberculosis H37Rv (MTB H37Rv) strain using MTT-MABA assay. All the aziridine derivatives exhibited improved persuasive antitubercular activity against MTB H37Rv in comparison with standard drugs. Among the tested compounds, 2-(naphthalene-1-yloxy) methyl aziridine (5b), 2-(naphthalene-2-yloxy)methylaziridine (5c), 2-(m-tolyloxymethyl)aziridine (5e), 2-(3-(4-methoxyphenyl)-1-phenylalloxy)methylaziridine (12b) and 2-(3-(2-chlorophenyl)-1-phenylallyloxy)methylaziridine (12c) revealed promising activity against MTB H37Rv. Specifically, compound 5b and 12 b showed three-times more active (MIC = 0.5 μg/mL) than the standard drugs ethambutol (MIC = 1.56 μg/mL) and ciprofloxacin (MIC = 1.56 μg/mL).
Potassium Base-Catalyzed Michael Additions of Allylic Alcohols to α,β-Unsaturated Amides: Scope and Mechanistic Insights
Kurouchi, Hiroaki,Sai, Masahiro
, p. 3585 - 3591 (2021/06/27)
We report herein the first KHMDS-catalyzed Michael additions of allylic alcohols to α,β-unsaturated amides through allylic isomerization. The reaction proceeds smoothly in the presence of only 5 mol% of KHMDS to afford a variety of 1,5-ketoamides in high yields. Mechanistic investigations, including experimental and computational studies, reveal that the KHMDS-catalyzed in-situ generation of the enolate from the allylic alcohol through a tunneling-assisted 1,2-hydride shift is the key to the success of this transformation. (Figure presented.).
Potassium Base-Promoted Diastereoselective Synthesis of 1,3-Diols from Allylic Alcohols and Aldehydes through a Tandem Allylic-Isomerization/Aldol–Tishchenko Reaction
Sai, Masahiro
, p. 4053 - 4056 (2021/10/25)
This study reports the first base-promoted aldol–Tishchenko reactions of allylic alcohols with aldehydes initiated by allylic isomerization. The reaction enables the diastereoselective synthesis of a variety of 1,3-diols with three contiguous stereogenic centers. Unlike commonly reported systems, our method allows the use of readily available allylic alcohols as nucleophiles instead of enolizable aldehydes and ketones.
Enantioselective Reduction of Ketones Catalyzed by Rare-Earth Metals Complexed with Phenoxy Modified Chiral Prolinols
Song, Peng,Lu, Chengrong,Fei, Zenghui,Zhao, Bei,Yao, Yingming
, p. 6093 - 6100 (2018/05/23)
Enantioselective reduction of ketones and α,β-unsaturated ketones by pinacolborane (HBpin) has been well-established by using chiral rare-earth metal catalysts with phenoxy modified prolinols. A number of highly optically active alcohols were obtained from reduction of simple ketones catalyzed by ytterbium complex 1 [L4Yb(L4H)] (H2L4 = (S)-2- tert-butyl-6-((2-(hydroxydiphenylmethyl)pyrrolidin-1-yl)methyl)phenol). Moreover, α,β-unsaturated ketones were selectively reduced to a wide range of chiral allylic alcohols with excellent yields, high enantioselectivity, and complete chemoselectivity, catalyzed by a single component chiral ytterbium complex 2 [L1Yb(L1H)] (H2L1 = (S)-2,4-di-tert-butyl-6-((2-(hydroxydiphenylmethyl)pyrrolidin-1-yl)methyl)phenol).
Direct Reduction of Allylic Alcohols Using Isopropanol as Reductant
Sai, Masahiro
, p. 3482 - 3487 (2018/09/14)
The lithium cation-catalyzed direct reduction of allylic alcohols to alkenes using isopropanol as a hydride donor was developed. The hydride transfer of the in situ-generated lithium isopropoxide to an allylic cation is the key process in this transformation. The reaction generates only water and acetone as byproducts, which highlights the synthetic utility of this method. (Figure presented.).
Bi(OTf)3 catalyzed disproportionation reaction of cinnamyl alcohols
Chan, Chieh-Kai,Tsai, Yu-Lin,Chang, Meng-Yang
, p. 3368 - 3376 (2017/05/22)
Bi(OTf)3 catalyzed disproportionation reaction of cinnamyl alcohols provides chalcones and benzyl styrenes. The use of various metal triflates is investigated herein for facile and efficient redox transformation. A plausible mechanism has been proposed.
Enantiospecific, nickel-catalyzed cross-couplings of allylic pivalates and arylboroxines
Srinivas, Harathi D.,Zhou, Qi,Watson, Mary P.
supporting information, p. 3596 - 3599 (2014/07/21)
We have developed an enantiospecific, nickel-catalyzed cross-coupling of unsymmetric 1,3-disubstituted allylic pivalates with arylboroxines. The success of this reaction relies on the use of BnPPh2 as a supporting ligand for the nickel(0) catalyst and NaOMe as a base. This method shows excellent functional group tolerance and broad scope in both the allylic pivalate and arylboroxine, enabling the preparation of 1,3-diaryl allylic products in high yields with excellent levels of regioselectivity and stereochemical fidelity.
Lithium amidoborane, a highly chemoselective reagent for the reduction of α,β-unsaturated ketones to allylic alcohols
Xu, Weiliang,Zhou, Yonggui,Wang, Ruimin,Wu, Guotao,Chen, Ping
experimental part, p. 367 - 371 (2012/01/13)
Lithium amidoborane (LiNH2BH3, LiAB for short), is capable of chemoselectively reducing α,β-unsaturated ketones to the corresponding allylic alcohols at ambient temperature. A mechanistic study shows that the reduction is via a double hydrogen transfer process. The protic H(N) and hydridic H(B) in amidoborane add to the O and C sites of the carbonyl group, respectively.
Asymmetric additive-free aryl addition to aldehydes using perhydrobenzoxazines as ligands and boroxins as aryl source
Infante, Rebeca,Nieto, Javier,Andres, Celia
experimental part, p. 6691 - 6699 (2011/11/04)
A highly efficient enantioselective aryl addition to aldehydes using boroxins as aryl source and conformationally restricted perhydro-1,3- benzoxazines as ligands is reported. Both enantiomeric forms of chiral arylphenylmethanols and 1,1′-disubstituted diarylmethanols are afforded with excellent yields and enantioselectivities using the same ligand by means of an appropriate combination of boroxin and aromatic aldehyde. The enantiocontrol is not significantly influenced by electronic effects or steric hindrance, even with substituted boroxins. Very homogeneous ee's are reached when substituted arylboroxins are employed, without the use of any class of additive or pre-treatment.