42565-22-0Relevant academic research and scientific papers
NICKEL-CATALYZED OLIGOMERIZATION OF FUNCTIONALIZED CONJUGATED DIENES
Tenaglia, A.,Brun, P.,Waegell, B.
, p. 343 - 358 (1985)
The cyclodimerization of several functionalized dienes with nickel(0) catalysts has been studied.When a functional group, such as a methoxycarbonyl or a trimethylsiloxy group, is bonded directly to the terminal carbon of the diene grouping, a completely regio- and stereo-selective dimerization is observed and trans-1,2-disubstituted cycloocta-3,7-dienes are formed in good yields (80-90percent).When one carbon atom separates the functional group from the diene group, the yield drops significantly (to 30percent), and the stereoselectivity and the clean nature of the reaction are completely lost.The effect of the nature of the nickel catalyst and the influence of the reductive organoaluminum species are discussed.The particular structure and the stereochemical features of the cyclooctadiene derivatives allow a better understanding of the various steps involved in the catalytic process.A reaction mechanism is proposed.
Hydrogen Bonding-Assisted Enhancement of the Reaction Rate and Selectivity in the Kinetic Resolution of d,l-1,2-Diols with Chiral Nucleophilic Catalysts
Fujii, Kazuki,Mitsudo, Koichi,Mandai, Hiroki,Suga, Seiji
supporting information, p. 2778 - 2788 (2017/08/23)
An extremely efficient acylative kinetic resolution of d,l-1,2-diols in the presence of only 0.5 mol% of binaphthyl-based chiral N,N-4-dimethylaminopyridine was developed (selectivity factor of up to 180). Several key experiments revealed that hydrogen bonding between the tert-alcohol unit(s) of the catalyst and the 1,2-diol unit of the substrate is critical for accelerating the rate of monoacylation and achieving high enantioselectivity. This catalytic system can be applied to a wide range of substrates involving racemic acyclic and cyclic 1,2-diols with high selectivity factors. The kinetic resolution of d,l-hydrobenzoin and trans-1,2-cyclohexanediol on a multigram scale (10 g) also proceeded with high selectivity and under moderate reaction conditions: (i) very low catalyst loading (0.1 mol%); (ii) an easily achievable low reaction temperature (0 °C); (iii) high substrate concentration (1.0 M); and (iv) short reaction time (30 min). (Figure presented.).
Photochirogenic nanosponges: phase-controlled enantiodifferentiating photoisomerization of (Z)-cyclooctene sensitized by pyromellitate-crosslinked linear maltodextrin
Liang, Wenting,Zhao, Meiling,Wei, Xueqin,Yan, Zhiqiang,Wu, Wanhua,Caldera, Fabrizio,Trotta, Francesco,Inoue, Yoshihisa,Su, Dan,Zhong, Zhihui,Yang, Cheng
, p. 17184 - 17192 (2017/03/30)
Linear maltodextrin (LM) was cross-linked by pyromellitic dianhydride to afford LM polymers of different cross-linking degrees. When soaked in water, these cross-linked LM polymers (nanosponges (NSs)), evolved into several phases from sol to suspension, then to flowing gel, and finally to rigid gel with an increase in their content. Enantiodifferentiating photoisomerization of (Z)-cyclooctene (1Z) to chiral (E)-isomer (1E), which was employed as a benchmark reaction to quantitatively assess the environmental-to-molecular chirality transfer process, was performed in aqueous media containing these pyromellitate-crosslinked LM-NSs in different phases. The enantiomeric excess (ee) of 1E obtained was relatively insensitive to the phases at least up to the flowing gel phase, but became highly sensitive in the rigid gel phase, exhibiting an abrupt drop in the early rigid gel phase followed by a rapid recovery in the late rigid gel phase. A comparison with the phase-dependent ee profiles previously reported for similar pyromellitate-crosslinked cyclodextrin (CD)- and cyclic nigerosylnigerose (CNN)-NSs revealed that the chiral void space created around the pyromellitate linker in NS is responsible for the dramatic changes in ee in the rigid gel phase, whereas the inherent host cavity in CD/CNN plays only limited roles in the supramolecular photochirogenesis mediated by the sensitizer-crosslinked NSs. The latter insight allows us to further expand the applicable range of the present concept and methodology by employing a much wider variety of oligosaccharides as well as substrates and sensitizing cross-linkers.
Alcohol cross-coupling for the kinetic resolution of diols via oxidative esterification
Hofmann, Christine,Schümann, Jan M.,Schreiner, Peter R.
, p. 1972 - 1978 (2015/02/19)
We present an organocatalytic C-O-bond cross-coupling strategy to kinetically resolve racemic diols with aromatic and aliphatic alcohols, yielding enantioenriched esters. This one-pot protocol utilizes an oligopeptide multicatalyst, m-CPBA as the oxidant, and N,N-diisopropylcarbodiimide as the activating agent. Racemic acyclic diols as well as trans-cycloalkane-1,2-diols were kinetically resolved, achieving high selectivities and good yields for the products and recovered diols.
En route to multicatalysis: Kinetic resolution of trans-cycloalkane-1,2- diols via oxidative esterification
Hofmann, Christine,Schuler, Soeren M. M.,Wende, Raffael C.,Schreiner, Peter R.
, p. 1221 - 1223 (2014/01/17)
We demonstrate the application of a multicatalyst to the oxidation of a broad variety of aldehydes and subsequent enantioselective esterification of the incipient acids with (±)-trans-cycloalkane-1,2-diols. This reaction operates well with a multicatalyst bearing two independent catalytic moieties that provide monoprotected 1,2-diols in one pot.
Enantioselective biooxidation of racemic trans-cyclic vicinal diols: One-pot synthesis of both enantiopure (S,S)-cyclic vicinal diols and (R)-α-hydroxy ketones
Zhang, Jiandong,Xu, Tingting,Li, Zhi
supporting information, p. 3147 - 3153 (2013/12/04)
Highly regio- and enantioselective alcohol dehydrogenases BDHA (2,3-butanediol dehydrogenase from Bacillus subtilis BGSC1A1), CDDHPm (cyclic diol dehydrogenase from Pseudomonas medocina TA5), and CDDHRh (cyclic diol dehydrogenase from Rhodococcus sp. Moj-3449) were discovered for the oxidation of racemic trans-cyclic vicinal diols. Recombinant Escherichia coli expressing BDHA was engineered as an efficient whole-cell biocatalyst for the oxidation of (±)-1,2-cyclopentanediol, 1,2-cyclohexanediol, 1,2-cycloheptane-diol, and 1,2-cyclooctanediol, respectively, to give the corresponding (R)-α-hydroxy ketones in >99% ee and (S,S)-cyclic diols in >99% ee at 50% conversion in one pot. Escherichia coli (BDHA-LDH) co-expressing lactate dehydrogenase (LDH) for intracellular regeneration of NAD+ catalyzed the regio- and enantioselective oxidation of (±)-1,2-dihydroxy-1,2,3,4- tetrahydronaphthalene to produce the corresponding (R)-α-hydroxy ketone in >99% ee and (S,S)-cyclic diol in 96% ee at 49% conversion. Preparative biotransformations were also demonstrated. Thus, a novel and useful method for the one-pot synthesis of both vicinal diols and α-hydroxy ketones in high ee was developed via high Copyright
Enhanced rate and selectivity by carboxylate salt as a basic cocatalyst in chiral N-heterocyclic carbene-catalyzed asymmetric acylation of secondary alcohols
Kuwano, Satoru,Harada, Shingo,Kang, Bubwoong,Oriez, Raphael,Yamaoka, Yousuke,Takasu, Kiyosei,Yamada, Ken-Ichi
supporting information, p. 11485 - 11488 (2013/09/02)
The rate and enantioselectivity of chiral NHC-catalyzed asymmetric acylation of alcohols with an adjacent H-bond donor functionality are remarkably enhanced in the presence of a carboxylate cocatalyst. The degree of the enhancement is correlated with the basicity of the carboxylate. With a cocatalyst and a newly developed electron-deficient chiral NHC, kinetic resolution and desymmetrization of cyclic diols and amino alcohols were achieved with extremely high selectivity (up to s = 218 and 99% ee, respectively) at a low catalyst loading (0.5 mol %). This asymmetric acylation is characterized by a unique preference for alcohols over amines, which are not converted into amides under the reaction conditions.
Enantiomerically enriched trans-diols from alkenes in one pot: A multicatalyst approach
Hrdina, Radim,Mueller, Christian E.,Wende, Raffael C.,Wanka, Lukas,Schreiner, Peter R.
supporting information; experimental part, p. 2498 - 2500 (2012/04/10)
Multicatalysts consisting of non-natural oligopeptides with distinctly different catalytic moieties create molecular complexity in a multistep one-pot sequence starting from simple alkenes yielding highly enantiomerically enriched trans-diols. The Royal Society of Chemistry 2012.
Bronsted acid-catalyzed dihydroxylation of olefins in aqueous medium
Rosatella, Andreia A.,Afonso, Carlos A.M.
supporting information; experimental part, p. 2920 - 2926 (2012/01/03)
The trans-dihydroxylation of olefins occurs efficiently by aqueous hydrogen peroxide catalyzed by p-toluenesulfonic acid at 50°C, allowing the catalyst reuse and an outstanding substrate functional group tolerance such as tert-butoxycarbonylamino (BocNH), benzyloxycarbonylamino (CbzNH), benzyloxy (OBn), tosyloxy (OTs), hindered ketal, (2-trimethylsilyl)ethoxymethoxy (OSEM), benzylamino (NBz), benzyloxy (OBz) and free amino acid. Copyright
Kinetic resolution of trans-cycloalkane-1,2-diols via Steglich esterification
Hrdina, Radim,Mueller, Christian E.,Schreiner, Peter R.
supporting information; experimental part, p. 2689 - 2690 (2010/07/08)
We describe the efficient and highly enantioselective kinetic resolution of trans-cycloalkane-1,2-diols utilizing an enantioselective Steglich reaction with a variety of carboxylic acids that form the corresponding anhydrides in situ.
