64363-90-2Relevant academic research and scientific papers
Highly enantioselective organocatalytic oxidative kinetic resolution of secondary alcohols using chiral alkoxyamines as precatalysts: Catalyst structure, active species, and substrate scope
Murakami, Keiichi,Sasano, Yusuke,Tomizawa, Masaki,Shibuya, Masatoshi,Kwon, Eunsang,Iwabuchi, Yoshiharu
supporting information, p. 17591 - 17600 (2015/02/19)
The development and characterization of enantioselective organocatalytic oxidative kinetic resolution (OKR) of racemic secondary alcohols using chiral alkoxyamines as precatalysts are described. A number of chiral alkoxyamines have been synthesized, and their structure-enantioselectivity correlation study in OKR has led us to identify a promising precatalyst, namely, 7-benzyl-3-n-butyl-4-oxa-5-azahomoadamantane, which affords various chiral aliphatic secondary alcohols (ee up to >99%, krel up to 296). In a mechanistic study, chlorine-containing oxoammonium species were identified as the active species generated in situ from the alkoxyamine precatalyst, and it was revealed that the chlorine atom is crucial for high reactivity and enantioselectivity. The present OKR is the first successful example applicable to various unactivated aliphatic secondary alcohols, including heterocyclic alcohols with high enantioselectivity, the synthetic application of which is demonstrated by the synthesis of a bioactive compound.
Flexible stereoselective functionalizations of ketones through umpolung with hypervalent iodine reagents
Mizar, Pushpak,Wirth, Thomas
, p. 5993 - 5997 (2014/06/10)
The functionalization of carbonyl compounds in the α-position has gathered much attention as a synthetic route because of the wide biological importance of such products. Through polarity reversal, or "umpolung", we show here that typical nucleophiles, such as oxygen, nitrogen, and even carbon nucleophiles, can be used for addition reactions after tethering them to enol ethers. Our findings allow novel retrosynthetic planning and rapid assembly of structures previously accessible only by multistep sequences. A Nu approach: An efficient α-functionalization of ketones with a range of simple and useful nucleophiles is possible by using hypervalent iodine reagents (see scheme; Nu′ can be the Nu itself or a protected form of this nucleophile group).
Stereochemical study on an oxygen-directed olefin oxidation and subsequent oxygen cyclization: Differences between peracid and metal oxide-catalyzed hydroperoxide in oxidation reactions
Inoue, Aya,Misaki, Tomonori,Fujita, Morifumi,Okuyama, Tadashi,Sugimura, Takashi
, p. 833 - 837 (2013/08/23)
Optically active (2S,4R)-2-hydroxy-4-pentyl enol ether was prepared for the first time and subjected to hydroxy-directed oxidations at the olefinic group. Treatment with m-chloroperbenzoic acid and tert-butyl hydroperoxide/vanadium acetylacetonate resulte
Asymmetric α-oxyacylation of cyclic ketones
Smithen, Deborah A.,Mathews, Christopher J.,Tomkinson, Nicholas C.O.
supporting information; experimental part, p. 3756 - 3762 (2012/06/01)
Reaction of cyclic ketones with chiral N-alkyl-O-acyl hydroxylamines leads to the corresponding α-oxyacylated carbonyl compound in up to 89% ee. The levels of asymmetric induction were influenced by solvent polarity, acid strength and, to a lesser extent,
A multicatalyst system for the one-pot desymmetrization/oxidation of meso-1,2-alkane diols
Mueller, Christian E.,Hrdina, Radim,Wende, Raffael C.,Schreiner, Peter R.
supporting information; experimental part, p. 6309 - 6314 (2011/08/07)
Two is better than one: We demonstrate the viability of an organocatalytic reaction sequence along a short peptide backbone that carries two independent catalytic functionalities, which allow the rapid, one-pot acylative desymmetrization and oxidation of meso-alkane-1,2-diols to the corresponding acetylated acetoins with good yields and enantioselectivities (see scheme). Copyright
Lead(IV) acetate oxidative ring-opening of 2,3-epoxy primary alcohols: A new entry to optically active α-hydroxy carbonyl compounds
Alvarez-Manzaneda, Enrique,Chahboun, Rachid,Alvarez, Esteban,Alvarez-Manzaneda, Ramón,Mu?oz, Pedro E.,Jiménez, Fermín,Bouanou, Hanane
experimental part, p. 4017 - 4020 (2011/08/21)
The treatment of 2,3-epoxy primary alcohols with lead(IV) acetate (LTA) leads to α-acetoxy aldehydes or α-acetoxy ketones, through the nucleophilic ring-opening of an intermediate oxonium and the subsequent carbon-carbon bond cleavage. This reaction repre
Lead(IV) acetate mediated cleavage of β-hydroxy ethers: Enantioselective synthesis of α-acetoxy carbonyl compounds
Alvarez-Manzaneda, Enrique,Chahboun, Rachid,Alvarez, Esteban,Alvarez-Manzaneda, Ramón,Mu?oz, Pedro E.,Jimenez, Fermín,Bouanou, Hanane
experimental part, p. 8910 - 8917 (2011/12/01)
α-Acetoxy aldehydes or α-acetoxy ketones can be efficiently synthesized by treating 2,3-epoxy primary alcohols with lead tetraacetate. The reaction, which proceeds with complete regio- and stereoselectivity facilitates the enantioselective synthesis of α-acetoxy carbonyl compounds from allyl alcohols, via Sharpless epoxidation. Cyclic β-hydroxy ethers, with an oxygenated five-, six- or seven-membered ring, are transformed into α-acetoxy ethers.
One-Pot desymmetrization of meso-l,2-hydrocarbon diols through acylation and oxidation
Mueller, Christian E.,Zell, Daniela,Schreiner, Peter R.
supporting information; experimental part, p. 9647 - 9650 (2010/04/28)
Avoid racemization! Short lipophilic oligopeptides utilizing nucleophilic N-jt-methyl histidine residues catalyze the desymmetrization of wieso-l,2-diols with enantiomeric ratios of up to 94:6. Direct one-pot oxidation, which avoids the well-known racemiz
Chemoenzymatic dynamic kinetic resolution of allylic alcohols: A highly enantioselective route to acyloin acetates
Bogar, Krisztian,Vidal, Pilar Hoyos,Alcantara Leon, Andres R.,Baeckvall, Jan-E.
, p. 3401 - 3404 (2008/02/12)
Dynamic kinetic resolution (DKR) of a series of sterically hindered allylic alcohols has been conducted with Candida antarctica lipase B (CALB) and ruthenium catalyst 1. The optically pure allylic acetates obtained were subjected to oxidative cleavage to
First lipase catalysed resolution of epoxy enol esters
Gravil, Sébastien,Veschambre, Henri,Chênevert, Robert,Bolte, Jean
, p. 6153 - 6157 (2007/10/03)
We report the first enzyme-catalysed kinetic resolution of epoxy enol esters. The lipase-promoted hydrolysis of these compounds provided α-hydroxyketones or α-hydroxyaldehydes (arising from the spontaneous rearrangement of the epoxy enols) and the residual esters with moderate to good enantioselectivity (E up to 100).
