40760-35-8Relevant academic research and scientific papers
Synthesis of (-)-6,7-Dideoxysqualestatin H5 by Carbonyl Ylide Cycloaddition-Rearrangement and Cross-electrophile Coupling
Fegheh-Hassanpour, Younes,Arif, Tanzeel,Sintim, Herman O.,Al Mamari, Hamad H.,Hodgson, David M.
, p. 3540 - 3543 (2017)
An asymmetric synthesis of (-)-6,7-dideoxysqualestatin H5 is reported. Key features of the synthesis include the following: (1) highly diastereoselective n-alkylation of a tartrate acetonide enolate and subsequent oxidation-hydrolysis to provide an asymmetric entry to a β-hydroxy-α-ketoester motif; (2) facilitation of Rh(II)-catalyzed cyclic carbonyl ylide formation-cycloaddition by co-generation of keto and diazo functionality through ozonolysis of an unsaturated hydrazone; and (3) stereoretentive Ni-catalyzed Csp3-Csp2 cross-electrophile coupling between tricarboxylate core and unsaturated side chain to complete the natural product.
Iron-Catalyzed Ring-Closing C?O/C?O Metathesis of Aliphatic Ethers
Biberger, Tobias,Makai, Szabolcs,Lian, Zhong,Morandi, Bill
supporting information, p. 6940 - 6944 (2018/05/14)
Among all metathesis reactions known to date in organic chemistry, the metathesis of multiple bonds such as alkenes and alkynes has evolved into one of the most powerful methods to construct molecular complexity. In contrast, metathesis reactions involving single bonds are scarce and far less developed, particularly in the context of synthetically valuable ring-closing reactions. Herein, we report an iron-catalyzed ring-closing metathesis of aliphatic ethers for the synthesis of substituted tetrahydropyrans and tetrahydrofurans, as well as morpholines and polycyclic ethers. This transformation is enabled by a simple iron catalyst and likely proceeds via cyclic oxonium intermediates.
General, Auxiliary-Enabled Photoinduced Pd-Catalyzed Remote Desaturation of Aliphatic Alcohols
Parasram, Marvin,Chuentragool, Padon,Wang, Yang,Shi, Yi,Gevorgyan, Vladimir
, p. 14857 - 14860 (2017/10/31)
A general, efficient, and site-selective visible light-induced Pd-catalyzed remote desaturation of aliphatic alcohols into valuable allylic, homoallylic, and bis-homoallylic alcohols has been developed. This transformation operates via a hybrid Pd-radical mechanism, which synergistically combines the favorable features of radical approaches, such as a facile remote C-H HAT step, with that of transition-metal-catalyzed chemistry (selective β-hydrogen elimination step). This allows achieving superior degrees of regioselectivity and yields in the desaturation of alcohols compared to those obtained by the state-of-the-art desaturation methods. The HAT at unactivated C(sp3)-H sites is enabled by the easily installable/removable Si-auxiliaries. Formation of the key hybrid alkyl Pd-radical intermediates is efficiently induced by visible light from alkyl iodides and Pd(0) complexes. Notably, this method requires no exogenous photosensitizers or external oxidants.
Synthesis of perhydrofuro[2,3-b]furans from isopentenyl alcohol through carbonyl-ene and wacker-type reactions
Alonso, Francisco,Rodriguez-Fernandez, Mamen,Sanchez, Daniel,Yus, Miguel
, p. 6459 - 6469 (2011/12/05)
A range of 2-substituted perhydrofuro[2,3-b]furans have been synthesized in a stereoselective manner through a sequence involving the Lewis-acid catalyzed carbonyl-ene reaction of a protected isopentenyl alcohol with a variety of enophiles, deprotection of the corresponding monoprotected diols, and palladium-catalyzed intramolecular acetalization under Wacker-type reaction conditions. A new synthetic approach toward the synthesis of perhydrofuro[2,3-b]furans is described. The strategy is based on the carbonyl-ene reaction for a protected isopentenyl alcohol with several activated enophiles followed by deprotection and palladium-catalyzed intramolecular acetalization. Copyright
The preparation and structures of several cross-conjugated allenes ("allenic dendralenes")
Lehrich, Friedhelm,Hopf, Henning,Grunenberg, Joerg
scheme or table, p. 2705 - 2718 (2011/06/25)
The cross-conjugated allenes ("allenic dendralenes") 2-allenylbuta-1,3-diene (2), 1,1-divinylallene (3, prepared here as the methyl derivative 49), and 1,1-diallenylethene (4) are prepared either by S N2′-substitution processes from appropriate allenic or acetylenic precursors or by base-catalyzed isomerizations of propargylic substrates. Thermal elimination/isomerization routes to these highly unsaturated hydrocarbons require reaction conditions under which these allenes undergo secondary transformations. The new oligoolefins, the structures of which have been calculated by MP2 methods, are interesting substrates for addition and isomerization reactions. The phenomenon of cross-conjugation is extended to allenes; the resulting oligoolefins are predicted to become useful dienes for multiple-Diels-Alder additions allowing the rapid construction of complex carbon frameworks.
DIMETHYLALUMINUM CHLORIDE CATALYZED ENE REACTIONS OF ALDEHYDES.
Snider,Rodini,Kirk,Cordova
, p. 555 - 563 (2007/10/02)
Dimethylaluminum chloride, which is a mild Lewis acid and a proton scavenger, catalyzes the ene reactions of aliphatic and aromatic aldehydes with alkenes containing a disubstituted vinylic carbon. Proton-initiated rearrangements do not occur, since the alcohol-Lewis acid complex formed in the ene reaction reacts rapidly to give methane and a nonacidic aluminum alkoxide. Formaldehyde and excess Me//2AlCl give good yields of ene adducts with all types of alkenes. With 1 equiv of Me//2AlCl, formaldehyde and mono- and 1,2-disubstituted alkenes give gamma -chloro alcohols resulting from cis addition of chlorine and hydroxymethyl groups to the double bond. This work is pertinent to the synthesis of alcohols.
Reaction of Dinitrogen Tetraoxide with Hydrophilic Olefins: Synthesis of Citric and 2-Hydroxy-2-methylbutanedioic Acids
Wilkes, John B.,Wall, Robert G.
, p. 247 - 250 (2007/10/02)
Liquid olefins typically react with N2O4 by free-radical reactions to form dinitro and nitronitrite derivatives.Introduction of hydrophilic substituents into 1-olefins altered the course of the reaction of the olefins with N2O4 in aqueous HNO3.Citric acid was formed in 64 mol percent yield by the reaction of 3-methylene-1,5-pentanediol with N2O4 in aqueous HNO3.Similarly, 2-hydroxy-2-methylbutanedioic acid was made from 3-methyl-3-buten-1-ol in 88percent yield.These results are explained by solution of the hydrophilic olefins in aqueous HNO3-N2O4 and addition of N2O4 to the double bond as NO+ and NO3- ions to yield nitrosonitrates, which react further to give the final products.
Hydroxylation of unsaturated diols to prepare novel tetraols
-
, (2008/06/13)
Tetraols of the formula EQU1 wherein R is hydrogen or hydroxy; R' is hydrogen or hydroxy and differs from R; n is an integer from 1 to about 6; and m is an integer from 0 to 6, are prepared by epoxidation of select unsaturated diols to form 1,2- epoxides, followed by hydroxylation of the epoxides.
