39864-10-3Relevant academic research and scientific papers
Asymmetric synthesis of (R)-limonene and (S)-cembrene-A by an intramolecular cyclization reaction using a chiral leaving group
Ishihara,Nakamura,Yamamoto
, p. 1113 - 1116 (2001)
A six-membered monocyclic terpene, (R)-limonene, and a 14-membered monocyclic diterpene, (S)-cembrene-A, have been synthesized, respectively, by new enantioselective intramolecular cyclization reactions of neryl ether and (all-E)-geranylgeranyl ether using an (R)- 1,1′-binaphthyl-2-benzoxy-2′-oxy auxiliary as a chiral leaving group in the presence of tin(IV) chloride.
Stereochemistry of Palladium(II)-induced Ring-opening of the Cyclopropane in a Vinylcyclopropane. Chloropalladation of Car-2-ene
Ahmad, Mesbah U.,Baeckvall, Jan-E.,Nordberg, Ruth E.,Norin, Torbjoern,Stroemberg, Sture
, p. 321 - 323 (1982)
Reaction of (+)-car-2-ene (1) with (MeCN)2PdCl2 produces a mixture of isomeric ?-allylpalladium complexes (2) and (3), where (2) was shown to arise from inversion of configuration at the carbon attacked by the metal.
Enantioselective Tail-to-Head Cyclizations Catalyzed by Dual-Hydrogen-Bond Donors
Kutateladze, Dennis A.,Strassfeld, Daniel A.,Jacobsen, Eric N.
, p. 6951 - 6956 (2020/05/19)
Chiral urea derivatives are shown to catalyze enantioselective tail-to-head cyclization reactions of neryl chloride analogues. Experimental data are consistent with a mechanism in which ?-participation by the nucleophilic olefin facilitates chloride ionization and thereby circumvents simple elimination pathways. Kinetic and computational studies support a cooperative mode of catalysis wherein two molecules of the urea catalyst engage the substrate and induce enantioselectivity through selective transition state stabilization.
Allylic and allenic halide synthesis via NbCl5- and NbBr 5-mediated alkoxide rearrangements
Ravikumar,Yao, Lihua,Fleming, Fraser F.
supporting information; experimental part, p. 7294 - 7299 (2010/01/16)
(Chemical Equation Presented) Addition of NbCl5 or NbBr 5 to a series of magnesium, lithium, or potassium allylic or propargylic alkoxides directly provides allylic or allenic halides. Halogenation formally occurs through a metallahalo-[3,3] rearrangement, although concerted, ionic, and direct displacement mechanisms appear to operate competitively. Transposition of the olefin is equally effective for allylic alkoxides prepared by nucleophilic addition, deprotonation, or reduction. Experimentally, the niobium pentahalide halogenations are rapid, afford essentially pure (E)-allylic or -allenic halides after extraction, and are applicable to a range of aliphatic and aromatic alcohols, aldehydes, and ketones. 2009 American Chemical Society.
Lewis acid-activated chiral leaving group: Enantioselective electrophilic addition to prochiral olefins
Nakamura, Hiroko,Ishihara, Kazuaki,Yamamoto, Hisashi
, p. 5124 - 5137 (2007/10/03)
A new strategy using a BINOL derivative as a chiral leaving group and Lewis acid has been developed for enantioselective alkylation of prochiral olefins. (R)-2,2′-Bis[2-(trimethylsilyl)ethoxy- methyl]-1,1′-binaphthol is demonstrated to be an effective reagent for enantioselective hydroxymethylation of silyl enol ethers and trisubstituted alkenes. Electrophilic addition to prochiral olefins is accompanied by cleavage of an acetal that is dual activated by SnCl4 and the δ-effect of silicon through the SN2 substitution process. Enantioselective synthesis of cyclic terpenes is also described using this strategy.
Simple synthetic protocols for tertiary alkyl and allyl thiols
Gurudutt, K. N.,Rao, Sanjay,Srinivas, P.,Srinivas, S.
, p. 1169 - 1171 (2007/10/03)
Convenient preparative methods for tertiary alkyl and allyl thiols are described. Accordingly, thiolesters and thiocyanates, obtained from the reaction of SN1-active halides and appropriate zinc salts, on hydrolysis and LAH reduction respectively, afford the corresponding thiols in near quantitative yields. Besides the well known p-menth-1-ene-8-thiol, p-menthane-1-thiol, p-mentha-1,8-diene-6-thiol and 2-(2-phenyl)propane thiol have been prepared.
Semiempirical AM1 Calculations on the Competing 1- and 4-Alkylation of 2-Methylbuta-1,3-diene with Primary Allylic Cations
Martin, Ivar,Muks, Elvi
, p. 52 - 53 (2007/10/03)
The strict regioselectivity of the attack of various carbenium ions on 2-methylbuta-1,3-diene at C-1 is not valid in the case of primary-tertiary allylic cations (such as 2-5) which also attack at C-4 (≈20%), a phenomenon which is rationalized by a cyclic HOMO-LUMO interaction of isoprene and allylic cations.
Nucleophilic substitution of SN1-active halides using zinc salts: Preparation of thiolacetates
Gurudutt,Rao, Sanjay,Srinivas,Srinivas
, p. 3045 - 3050 (2007/10/02)
Tertiary alkyl, allylic and benzylic halides react with zinc thiolacetate, prepared in situ, under optimised conditions to yield the corresponding thiolacetates in moderate to good yields.
Anodic behaviour of limonene in low aqueous acetonitrile solutions of Cl(1-)
Caram, J. A.,Martins, M. E.,Gros, E. G.,Marschoff, C. M.
, p. 1757 - 1762 (2007/10/02)
The anodic behaviour of limonene on Pt electrodes was studied in LiCl solutions in acetonitrile with low water content.It was found that cis-6-acetamido-p-menth-1,8-diene is formed with acceptable yields.This compound is of interest as a potential intermediate for obtaining oxidation derivatives of limonene.Other products, among them the new compound 8-acetamido-2,4,8-trimethyl-4-chloromethyl-3-aza-bicyclonon-2-ene, were identified.Reaction routes are proposed.
SOLVOLYTIC DISPLACEMENT OF ALKYL HALIDES BY METAL SALTS. PREPARATIVE PROCEDURES FOR ALLYL-, BENZYL- AND TERTIARY ALKYL-OXY DERIVATIVES USING THE ZINC SALTS
Gurudutt, K. N.,Ravindranath, B.,Srinivas, P.
, p. 1843 - 1846 (2007/10/02)
Reaction of allylic, benzylic and tertiary alkyl halides with zinc oxide in protic solvents leads to the formation of the corresponding alcohols, ethers and esters in good yields.The scope and limitations of this reaction have been examined.The possible involvement of ion quadruplets in the reaction is suggested.
