20056-56-8Relevant academic research and scientific papers
Nickel-Catalyzed C-O Bond-Cleaving Alkylation of Esters: Direct Replacement of the Ester Moiety by Functionalized Alkyl Chains
Liu, Xiangqian,Jia, Jiaqi,Rueping, Magnus
, p. 4491 - 4496 (2017/07/24)
Two efficient protocols for the nickel-catalyzed aryl-alkyl cross-coupling reactions using esters as coupling components have been established. The methods enable the selective oxidative addition of nickel to acyl C-O and aryl C-O bonds and allow the aryl-alkyl cross-coupling via decarbonylative bond cleavage or through cleavage of a C-O bond with high efficiency and good functional group compatibility. The protocols allow the streamlined, unconventional utilization of widespread ester groups and their precursors, carboxylic acids and phenols, in synthetic organic chemistry.
A 'meta effect' in the fragmentation reactions of ionised alkyl phenols and alkyl anisoles
Bouchoux, Guy,Sablier, Michel,Miyakoshi, Tetsuo,Honda, Takashi
scheme or table, p. 539 - 546 (2012/09/22)
The competition between benzylic cleavage (simple bond fission [SBF]) and retro-ene rearrangement (RER) from ionised ortho, meta and para RC 6H4OH and RC6H4OCH3 (R = n-C3H7, n-C4H9, n-C5H11, n-C7H15, n-C9H19, n-C 15H31) is examined. It is observed that the SBF/RER ratio is significantly influenced by the position of the substituent on the aromatic ring. As a rule, phenols and anisoles substituted by an alkyl group in meta position lead to more abundant methylene-2,4-cyclohexadiene cations (RER fragmentation) than their ortho and para homologues. This 'meta effect' is explained on the basis of energetic and kinetic of the two reaction channels. Quantum chemistry computations have been used to provide estimate of the thermochemistry associated with these two fragmentation routes. G3B3 calculation shows that a hydroxy or a methoxy group in the meta position destabilises the SBF and stabilises the RER product ions. Modelling of the SBF/RER intensities ratio has been performed assuming two single reaction rates for both fragmentation processes and computing them within the statistical RRKM formalism in the case of ortho, meta and para butyl phenols. It is clearly demonstrated that, combining thermochemistry and kinetics, the inequality (SBF/RER) metaorthopara holds for the butyl phenols series. It is expected that the 'meta effect' described in this study enables unequivocal identification of meta isomers from ortho and para isomers not only of alkyl phenols and alkyl anisoles but also in other alkyl benzene series. Copyright
Design of liquid crystalline block molecules with nonconventional mesophase morphologies: Calamitic bolaamphiphiles with lateral alkyl chains
Koelbel,Beyersdorff,Xiao Hong Cheng,Tschierske,Kain,Diele
, p. 6809 - 6818 (2007/10/03)
Novel bolaamphiphiles, consisting of a biphenyl rigid core, polar 2,3-dihydroxypropoxy groups at each terminal end, and an additional long alkyl chain in a lateral position have been synthesized. The structures of these ternary block molecules were systematically changed by variation of the length and position of the alkyl chain, by introduction of additional spacer units between one of the 2,3-dihydroxypropyl groups and the rigid core, and by replacement of one of the 2,3-dihydroxypropoxy groups by a single hydroxy group. The influence of these structural variations on the liquid crystalline properties of these new materials was investigated by polarized-light microscopy, differential scanning calorimetry, and X-ray diffraction. These investigation have shown that, by elongation of the lateral chain, a transition from a smectic monolayer structure (SmA1) via a strongly distorted layer structure (SmA+), a centered rectangular columnar phase (Colr/c2mm) and a noncentered rectangular columnar phase (Colr/p2gg) to a hexagonal columnar phase (Colh/p6mm) takes place. Elongation of the bolaamphiphilic core leads to the loss of the columnar phases, which are replaced by smectic phases, whereas reduction of its length favors the hexagonal columnar phase. This phase sequence is explained as a result of the microsegregation of the lateral alkyl chains from the rigid aromatic cores. The segregated alkyl chains are organized in columns that interrupt the smectic layers. The hydrogen bonding keep the bolaamphiphilic cores fixed end to end, so that they form networks of cylinders around the lipophilic columns. The space required by the alkyl chains with respect to the length of the bolaamphiphilic cores is restricted and largely determines the geometry of the cylinders, which leads to the observed phase sequence. The obtained mesophase morphologies, built up by three distinct sets of subspaces, are related to morphologies of some ternary block copolymers. Furthermore, the investigated compounds represent a novel class of materials, capable of forming supramolecular columnar mesophases.
Alkylation of Aldehyde (Arenesulfonyl)hydrazones with Trialkylboranes
Kabalka, George W.,Maddox, John T.,Bogas, Ekaterini,Kelley, Shane W.
, p. 3688 - 3695 (2007/10/03)
(Arenesulfonyl)hydrazone derivatives of aryl aldehydes are readily alkylated by trialkylboranes in the presence of base to generate new organoboranes that may be converted to the corresponding substituted alkanes or alcohols depending upon the reaction conditions chosen. Both tosyl- and trisylhydrazone derivatives can be utilized in the reaction, which tolerates a variety of functional groups, making it a versatile alternative to both the Grignard and Suzuki-coupling reactions.
Reduction of Monobenzylic Alcohols with Sodium Borohydride/Trifluoroacetic Acid
Nutaitis, Charles F.,Bernardo, Joseph E.
, p. 487 - 493 (2007/10/02)
Sodium borohydride/trifluoroacetic acid readily effects the reduction of monobenzylic alcohols to afford the corresponding hydrocarbons in moderate to high yields.
REDUCTIVE TRANSFORMATIONS WITH TRIMETHYLSILYL CHLORIDE-SODIUM IODIDE. A NEW SYNTHESIS OF 4H-1,3-OXAZINES
Ghera, Eugene,Maurya, Rakesh,Hassner, Alfred
, p. 4741 - 4744 (2007/10/02)
1-Arylalkenes and 1-arylalkanols are reduced to arylalkanes on heating with trimethylsilyl chloride/sodium iodide in CH3CN.Under similar conditions enones, dialkylated in the β-position of the double bond, give 4H-1,3-oxazines.
