20056-56-8Relevant articles and documents
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.
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.
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.
