78-27-3Relevant academic research and scientific papers
Halogen-Substituted Allenyl Ketones through Ring Opening of Nonstrained Cycloalkanols
Wu, Penglin,Ma, Shengming
supporting information, p. 2533 - 2537 (2021/04/13)
An efficient synthesis of halogen-substituted allenyl ketones via Ag-catalyzed oxidative ring opening of allenyl cyclic alcohols under mild reaction conditions has been achieved. The reaction features a wide substrate scope and excellent regioselectivity. The synthetic potential of the products has been demonstrated by their conversion to stereodefined alkenes and heterocyclic compounds.
Fluorocyclization of Allyl Alcohols and Amines to Access 3-Functionalized Oxetanes and Azetidines
Cao, Shanshan,Li, Linxuan,Liu, Zhaohong,Ning, Yongquan,Wu, Yong,Zanoni, Giuseppe,Zhang, Qi,Zhang, Xinyu
supporting information, p. 3674 - 3679 (2021/05/31)
An efficient method to prepare 3-functionalized oxetanes and azetidines has been realized by fluorocyclization of readily available 2-azidoallyl/2-alkoxyallyl alcohols and amines. Notably, this is the first example applying the fluorocyclization strategy to construct four-membered heterocycles. The pendant electron-donating group (-N3 or -OR) plays a crucial role in polarizing the C= C double bond and facilitating the cyclization process, as verified by DFT and experimental studies.
Enantio- And Diastereodivergent Construction of 1,3-Nonadjacent Stereocenters Bearing Axial and Central Chirality through Synergistic Pd/Cu Catalysis
Huo, Xiaohong,Ma, Shengming,Xiao, Junzhe,Zhang, Jiacheng,Zhang, Wanbin,Zhao, Ling
supporting information, p. 12622 - 12632 (2021/08/31)
In contrast to the widely explored methods for the asymmetric synthesis of molecules bearing a single stereocenter or adjacent stereocenters, the concurrent construction of 1,3-stereogenic centers in an enantio- and diastereoselective manner remains a challenge, especially in acyclic systems. Herein, we report an enantio- and diastereodivergent construction of 1,3-nonadjacent stereocenters bearing allenyl axial and central chirality through synergistic Pd/Cu-catalyzed dynamic kinetic asymmetric allenylation with racemic allenylic esters. The protocol is suitable for a wide range of substrates including the challenging allenylic esters with less sterically bulky substituents and provided chiral allenylic products bearing 1,3-nonadjacent stereocenters with high levels of enantio- and diastereoselectivities (up to >20:1 dr and >99% ee). Furthermore, several representative transformations involving axial-to-central chirality transfer were conducted, affording useful structural motifs containing nonadjacent stereocenters in a diastereodivergent manner.
ETHERS AND ESTERS OF 1-SUBSTITUTED CYCLOALKANOLS FOR USE AS AROMA CHEMICALS
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Page/Page column 52, (2020/05/21)
The present invention relates to the use of an ether or an ester of a 1 -substituted cycloalkanol or of mixtures of two or more ethers or esters of 1 -substituted cycloalkanols or of a stereoisomer thereof or of a mixture of two or more stereoisomers thereof as aroma chemicals; to the use thereof for modifying the scent character of a fragranced composition; to an aroma chemical composition containing an ether or an ester of a 1 -substituted cycloalkanol or of mixtures of two or more ethers or esters of 1 -substituted cycloalkanols or of a stereoisomer thereof or of a mixture of two or more stereoisomers thereof; and to a method of preparing a fragranced composition or for modifying the scent character of a fragranced composition. The invention further relates to specific ethers or esters of 1 -substituted cycloalkanols.
Oxidative Deprotection of p-Methoxybenzyl Ethers via Metal-Free Photoredox Catalysis
Ahn, Deok Kyun,Kang, Young Woo,Woo, Sang Kook
, p. 3612 - 3623 (2019/03/11)
An efficient and greener deprotection method for p-methoxybenzyl (PMB) ethers using a metal-free visible light photoredox catalyst and air and ammonium persulfate as the terminal oxidants is presented. Various functional groups and protecting groups were tolerated in the developed method to achieve good to excellent yields in short reaction times. Significantly, the developed method was compatible with PMB ethers derived from primary, secondary, and tertiary alcohols and a gram-scale reaction. Mechanistic studies support a proposed reaction mechanism that involves single electron oxidation of the PMB ether.
Synthesis of Imidazo[1,2-a]pyridines and Imidazo[2,1-b]thiazoles Attached to a Cycloalkyl or Saturated Heterocycle Containing a Tertiary Hydroxy Substitution
Chenna Reddy,Patil, Vineetkumar B.,Nawaz Khan, Fazlur Rahman,Saravanan, Vadivelu
, p. 1486 - 1497 (2019/04/04)
A new method has been developed for the synthesis of imidazo[1,2-a]pyridines, imidazo[2,1-b]thiazoles, and benzo[d]imidazo[2,1-b]thiazoles attached to a cycloalkyl or saturated heterocycle containing a tertiary hydroxy substitution. Readily available substituted 2-aminopyridines, 2-aminothiazoles, and 2-aminobenzothiazoles were treated with bromohydroxycycloalkyl ethanones to afford the desired products in good yields.
Neighboring Carbonyl Group Assisted Oxyacetoxylation of Propargylic Carboxylates with Retention of Chirality under Metal Free Condition
Pradhan, Tapas R.,Mohapatra, Debendra K.
supporting information, p. 3605 - 3611 (2019/07/04)
A metal-free oxyacetoxylation method of primary, secondary and tertiary propargylic carboxylates with retention of chirality was presented. The reaction proceeds through the intramolecular nucleophilic attack of the neighboring carbonyl group on an alkynyliodonium intermediate. The process is general with broad substrate scope and is amenable for application to a variety of propargyl carboxylates including those obtained from natural products. Insight into the mechanistic pathway by isotopic labelling (using H2O18 and D2O) and controlled experiments confirmed. (Figure presented.).
Method for efficiently preparing alkynol
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Paragraph 0036; 0037; 0038; 0043; 0044; 0045; 0046, (2018/12/14)
The invention relates to a method for efficiently preparing alkynol, belongs to the field of preparation of chemical intermediates and chemicals, and particularly relates to a preparation method of alkynol. The preparation method comprises the following steps that 1, alkali metal is added into an anhydrous alcohols solvent; an alcohol-alkali metal solution is prepared; 2, a compound I is added into the alcohol-alkali metal solution; uniform stirring is performed; cooling is performed to be 0 DEG C or below; 3, acetylene is introduced through being metered at normal pressure; alkynol is obtained; 4, the alkynol solution after reaction is neutralized by ammonium chloride and a same alcohol mixed suspension system; 5, the neutralized mixed suspension system is filtered; after alcohols are recovered from filter liquid, reduced pressure distillation is performed to obtain an alkynol product. The method overcomes the defect that under the existing harsh reaction conditions of high pressure,liquid ammonia and the like, the solid potassium hydroxide feeding difficulty is avoided; under the ordinary pressure condition, the ketone compounds are converted into alkynol at high conversion rate. The method has the advantages of high conversion rate, simple process and good product purity.
Rhodium-Catalyzed Asymmetric Conjugate Alkynylation/Aldol Cyclization Cascade for the Formation of α-Propargyl-β-hydroxyketones
Choo, Ken-Loon,Lautens, Mark
supporting information, p. 1380 - 1383 (2018/03/09)
A rhodium-catalyzed conjugate alkynylation/aldol cyclization cascade was developed. Densely functionalized cyclic α-propargyl-β-hydroxyketones were synthesized with simultaneous formation of a C(sp)-C(sp3) bond, a C(sp3)-C(sp3) bond, as well as three new contiguous stereocenters. The transformation was achieved with excellent enantio- and diastereoselectivities using BINAP as the ligand. The synthetic utility of the newly installed alkynyl moiety was exhibited by subjecting the products to an array of derivatizations.
Base-Catalyzed Borylation/B-O Elimination of Propynols and B2pin2 Delivering Tetrasubstituted Alkenylboronates
Kuang, Zhijie,Chen, Haohua,Yan, Jianxiang,Yang, Kai,Lan, Yu,Song, Qiuling
supporting information, p. 5153 - 5157 (2018/09/12)
An efficient approach to tetrasubstituted alkenylboronates via a cascade borylation/B-O elimination of propynols and B2pin2 was disclosed. A series of tetrasubstituted alkenylboronates were readily furnished with this strategy in good yields, with further transformations leading to tetrasubstituted alkenes and β-diketones demonstrating the synthetic potential of the alkenylboronates constructed by this strategy as versatile intermediates in organic synthesis.
