31147-63-4Relevant academic research and scientific papers
Synthesis and reactions of terpenyl diselenides functionalized with phenyl and naphthyl groups
?cianowski, Jacek,Szumera, Jakub,Kleman, Patryk,Pacu?a, Agata J.
, p. 238 - 245 (2016/03/16)
An efficient methodology for the synthesis of chiral terpenyl diselenides functionalized with phenyl and naphthyl groups has been developed. Using the reaction of sodium diselenide with terpenyl tosylates and chlorides, the corresponding diselenides derived from 8-phenyl menthol and isopinocampheol modified at the 10-position were obtained. Diselenides were transformed into electrophilic selenium reagents and tested in the asymmetric selenenylation of styrene. The effect of aryl groups on the enantioselectivity of the addition reaction was examined.
Hyperconjugation involving strained carbon-carbon bonds. Structural analysis of ester and ether derivatives and one-bond 13C- 13C coupling constants of α- And β-nopinol
Yeoh, Shinn Dee,Skene, Colin E.,White, Jonathan M.
, p. 311 - 319 (2013/02/25)
σC-C-σ*C-O interactions involving the strained carbon-carbon bonds of α- and β-nopinol, and their ester and ether derivatives have been demonstrated in the solid state using the variable oxygen probe. These hyperconjugative interactions are manifested as a strong response of the C-OR bond distance to the electron demand of the OR substituent. Although the effects upon the donor C-C bond distances are not large enough to be measurable by X-ray crystallography, they do result in systematic and measurable effects on the 13C-13C one-bond coupling constants. For the donor C-C bond, coupling constants decrease, consistent with weakening of this bond, while the intervening C-C bond coupling constants increase, consistent with bond strengthening, as the electron demand of OR increases.
Acceleration of the reduction of aldehydes and ketones using Mn(dpm)3 catalyst and phenylsilane in the presence of dioxygen
Magnus, Philip,Fielding, Mark R
, p. 6633 - 6636 (2007/10/03)
Saturated ketones and aldehydes are reduced to alcohols by phenylsilane and Mn(dpm)3(cat) in the presence of dioxygen.
Ion-molecule complexes in 1,2 alkyl shifts
Gappa, Andrea,Herpers, Ekkehard,Herrmann, Roland,Hülsewede, Volker,Kappert, Wilhelm,Klar, Matthias,Kirmse, Wolfgang
, p. 12096 - 12106 (2007/10/03)
The internal return of neutral leaving groups was studied in rearrangements of polycyclic systems (2-norpinyl → 2-norbornyl, endo- → exo-tricyclo[5.2.1.02.6]dec-8-yl, bicyclo[3.2.0]hept-2-yl → 7-norbornyl, and 4-protoadamantyl → 2-adamantyl). Acid catalysis was applied to 18O-labeled alcohols in aqueous organic solvents, to alcohols in methanol, and to ethers R-O-R′ in alcohols R″-OH. The leaving group was found to attack the migration origin in competition with solvent molecules. Return:exchange ratios were obtained from product distributions, either directly or by kinetic simulation (in cases of partial exchange prior to rearrangement). If departure and return of the leaving group occur on the same side of the carbon framework, return:exchange ratios ranging from 1 to 11.5 were observed. Less internal return was found for bridged than for open carbocations. Migration of the departing molecule to the opposite face (exo ? endo) or to a β carbon is a minor process (return:exchange ～ 0.1), in accordance with previous reports on inverting displacements and allylic 1,3 shifts. These data are rationalized in terms of short-lived ion-molecule (ion-dipole) complexes whose collapse competes with ligand exchange.
Trapping of the 6,6-Dimethylbicyclohept-2-yl Free Radical by SH2 Reaction upon Peracid
Fossey, Jacques,Lefort, Daniel,Sorba, Janine
, p. 3584 - 3587 (2007/10/02)
The free radical 6,6-dimethylbicyclohept-2-yl (7) has been obtained by decarboxylation of cis- or trans-6,6-dimethylbicycloheptane-2-peroxycarboxylic acids (6a and 6b). 7 trapped by reaction with the initial peracid gave a stereochemical mixture of α- and β-nopinol (8a and 8b).The ratio 8b/8a is around 12, independent of the initial peracid 6a or 6b and its initial concentrations.This value is mainly due to the steric effect of one of the methyl groups branched on C7 in 7.The structure of 7 is discussed.By a competitive reaction 7 undergoes ring opening to afford 2-(3-cyclohexenyl)-2-propyl free radical (9) which by reaction upon peracid leads to 2-(3-cyclohexenyl)-2-propanol (10). 7 was successfully trapped because its reaction with peracid is rapid enough.The ratio of the two alcohols 8/10 leads to an estimation of 1*106 M-1 s-1 for the rate constant of the reaction of 7 with peracids
Preparation of Optically Active, Functionalized cis-Δ6-1-Octalones
Boger, Dale L.,Mullican, Michael D.,Hellberg, Mark R.,Patel, Mona
, p. 1904 - 1911 (2007/10/02)
A preparation of optically pure, functionalized cis-Δ6-octalones starting with (-)-β-pinene (92percent ee) is detailed.The conversion of (-)-β-pinene to (-)-cis-nopinol (>97percent ee) and its utilization in the preparation of (4R,9R,10R)-(+)-4-(acetylamino)-9-(methoxycarbonyl)-cis-Δ6-1-octalone ethylene ketal (1), a cis-Δ6-1-octalone possessing the correct absolute configuration at three appropriately functionalized chiral centers characteristic of the morphine-related analgesics, is described.
