20047-25-0Relevant academic research and scientific papers
Intramolecular N-Me and N-H aminoetherification for the synthesis ofN-unprotected 3-amino-O-heterocycles
Paudyal, Mahesh P.,Wang, Mingliang,Siitonen, Juha H.,Hu, Yimin,Yousufuddin, Muhammed,Shen, Hong C.,Falck, John R.,Kürti, László
supporting information, p. 557 - 560 (2021/02/06)
A mild Rh-catalyzed method for synthesis of cyclic unprotected N-Me and N-H 2,3-aminoethers using an olefin aziridination-aziridine ring-opening domino reaction has been developed. The method is readily applicable to the stereocontrolled synthesis of a va
Chiral Selenide-Catalyzed Enantioselective Allylic Reaction and Intermolecular Difunctionalization of Alkenes: Efficient Construction of C-SCF3 Stereogenic Molecules
Liu, Xiang,Liang, Yaoyu,Ji, Jieying,Luo, Jie,Zhao, Xiaodan
supporting information, p. 4782 - 4786 (2018/04/17)
New approaches for the synthesis of enantiopure trifluoromethylthiolated molecules by chiral selenide-catalyzed allylic trifluoromethylthiolation and intermolecular difunctionalization of unactivated alkenes are disclosed. In these transformations, functi
Hot water-promoted cyclopropylcarbinyl rearrangement facilitates construction of homoallylic alcohols
Li, Pei-Fang,Yi, Cheng-Bo,Qu, Jin
, p. 5012 - 5021 (2015/05/05)
In refluxing 9 : 1 (v/v) H2O-1,4-dioxane and without an additional catalyst, the rearrangements of various types of cyclopropyl carbinols were attempted. It was found that the reactions generally gave homoallylic alcohols in good to very high chemical yields. Rearrangements of bicyclic or tricyclic cyclopropyl carbinols readily gave the desired ring-expanded cyclic homoallylic alcohols which are difficult to synthesize by other means.
Iridium-catalyzed asymmetric hydrogenation of 3,3-disubstituted allylic alcohols in ethereal solvents
Bernasconi, Maurizio,Ramella, Vincenzo,Tosatti, Paolo,Pfaltz, Andreas
supporting information, p. 2440 - 2444 (2014/03/21)
Ir-phosphinomethyl-oxazoline complexes have been identified as efficient, highly enantioselective catalysts for the asymmetric hydrogenation of 3,3-disubstituted allylic alcohols and related homoallylic alcohols. In contrast to other N,P ligand complexes, which require weakly coordinating solvents, such as dichloromethane, these catalysts perform well in more ecofriendly THF or 2-MeTHF. Their synthetic potential was demonstrated with the formal total synthesis of four bisabolane sesquiterpenes. Particularly high enantioselectivity values in the asymmetric hydrogenation of 3,3-disubstituted allylic alcohols and related homoallylic alcohols have been achieved with Ir-phosphinomethyloxazoline catalysts. In contrast to other N,P-ligand complexes, which require weakly coordinating solvents, such as CH 2Cl2, these catalysts perform well in more ecofriendly THF or 2-MeTHF (see scheme; CODa =a 1,5-cyclooctadiene). Copyright
Synthesis of 1,2,4-trioxepanes and 1,2,4-trioxocanes via photooxygenation of homoallylic alcohols
Singh, Chandan,Pandey, Shilpi,Saxena, Gunjan,Srivastava, Nisha,Sharma, Malvika
, p. 9057 - 9061 (2007/10/03)
(Chemical Equation Presented) Homoallylic alcohols 4a-d, easily accessible in two steps from cyclopropyl methyl ketone, underwent a highly regioselective reaction with singlet oxygen to yield γ-hydroxyhydroperoxides 5a-d in 57-72% yield. Acid-catalyzed reaction of 5a-d with acetone, cyclopentanone, and cyclohexanone furnished 1,2,4-trioxepanes 8a-d, 9a-d, and 10a-d in good yields. Homoallylic alcohol 12 also underwent a highly regioselective photooxygenation to yield δ-hydroxyhydroperoxide 13 in 67% yield, which on reaction with acetone, cyclopentanone, and cyclohexanone, furnished 1,2,4-trioxocanes 16-18 in 41-55% yield.
On the regioselectivity of Pd-catalyzed additions of organoboronic acids to unsymmetrical alkynes
Kim, Nakjoon,Kim, Ki Seong,Gupta, Aruna Kumar,Oh, Chang Ho
, p. 618 - 619 (2007/10/03)
The Pd-catalyzed reaction of unsymmetrical alkynes 1 with organoboronic acids 2 gave a mixture of products 3 and 4, whose ratios were controlled by the electronic as well as steric effects of the substrates 1.
β-Halogeno Ether Synthesis of Olefinic Alcohols: Stereochemistry of the Ring-scission of 2-Substituted 3-Halogenotetrahydro-pyrans and -furans
Crombie, Leslie,Wyvill, Robert D.
, p. 1983 - 1996 (2007/10/02)
The stereochemical outcome of the sodium ring-scission of 2-substituted 3-halogenotetrahydro-pyrans and -furans, with 2-substitution represented by alkyl, alkenyl or aryl, is presented.Although the cis- and the trans-tetrahydropyran scissions are hyghly stereoselective for (E)-5-substituted pent-4-enol, this stereoselectivity breaks down when the 2-substituent is conformationally undiscriminating (deuterium) or has substantial anomeric effects (methoxy).Consideration of this, along with conformational data from the preceding paper, provides an explanation of the stereoselectivity of the tetrahydropyran scission.Evidence against a radical, and for a carbanion intermediate is presented and a common, very rapidly inverting, 3-carbanion is considered to be formed from either cis- or trans-stereoisomers.Ring scission is also rapid (the carbanion cannot be trapped), but less rapid than carbanion inversion, and takes place before the slower conformational inversion can occur so that the (E)/(Z)-nature of the unsaturated alcohol produced is controlled by the initial tetrahydropyran conformation.The unstereospecific nature of the ring scission of both cis- and trans-2-alkyl-3-chlorotetrahydrofurans is explained as a consequence of their existence in conformational equilibria. The high stereoselectivity of the ring scission of cis- and trans-3-chloro-2,3-dimethyltetrahydropyrans, and the poor stereoselectivity of the scission of 2-alkyl-3-chloro-2-methyltetrahydrpyrans, is explained; the reaction of sodium with 2-butyl-3,3-dichlorotetrahydropyran is considered.Using the ring-scission of 3-chlor-2-ethyltetrahydropyran, short syntheses of (+/-)-endo-brevicomin are described to illustrate the utility of β-halogen ether synthesis.
Transformation of Carbon-Oxygen into Carbon-Carbon Bonds Mediated by Low-Valent Nickel Species
Wenkert, Ernest,Michelotti, Enrique L.,Swindell, Charles S.,Tingoli, Marco
, p. 4894 - 4899 (2007/10/02)
The substitution of alkoxy groups of enol ethers (1-methoxycyclohexenes, 1-methoxy-1-alkenes, and benzofuran) and aryl ethers (methoxynaphthalenes, cresyl methyl ethers, and dimethoxybenzenes) by hydrogen, alkyl groups, and aryl units, through Grignard reactions catalyzed by bis(triphenylphosphine)nickel dichloride or nickel dichloride, is described.The stereochemistry of the new reaction is portrayed, especially in connection with processes involving ring opening of dihydropyrans and dihydrofurans.The reaction has been applied to the synthesis of a termite trail pheromone and the acetate of the Douglas fir beetle aggregation pheromone.
