作者:Richard A. Bartsch、Leah P. Bitalac、Charles L. Cowey、Sadik Elshani、Mi-Ja Goo、Vincent J. Huber、Sheryl N. Ivy、Youngchan Jang、Russell J. Johnson、Jong Seung Kim、Elzbieta Luboch、Joseph A. Mcdonough、Michael J. Pugia、Byungki Son、Qiang Zhao
DOI:10.1002/jhet.5570370554
日期:2000.9
Synthetic routes to forty-four dibenzocrown ether alcohols are reported. The new crown ether com pounds are based on a sym-dibenzo-16-crown-5 platform. Most have a hydroxy group and an alkyl, aryl, aralkyl, alkenyl, alkynyl, or perfluoroalkyl group on the central carbon of the three-carbon bridge. Others have substituted benzene rings and either a hydroxy or -O(CH2)nOH group attached to the central
Silver-catalyzed Alkyl–Alkyl Homo-coupling of Grignard Reagents
作者:Takashi Nagano、Tamio Hayashi
DOI:10.1246/cl.2005.1152
日期:2005.8
Oxidative homo-coupling of alkyl Grignard reagents possessing β-hydrogens proceeded with high selectivity in the presence of silver tosylate (AgOTs) as a catalyst (1 mol %) and 1,2-dibromoethane as a reoxidant.
Claisenrearrangements of glycine crotyl ester enolates in the presence of chelating metal salts and chiral ligands provide ,-unsaturated amino acids in a highly stereoselective fashion. Best results are obtained with electron withdrawing protecting groups, isopropylates of aluminum and magnesium, and the cinchona alkaloids as chiral ligands. While the use of quinine gives rise to the (2R)-configured
Action d'organomagnesiens sur des sulfures et des sels de sulfonium allyliques catalysee par des sels cuivreux
作者:Y. Gendreau、J.F. Normant、J. Villieras
DOI:10.1016/s0022-328x(00)91810-2
日期:1977.12
Grignard reagents react with allylsulphides, in the presence of catalytic amounts of copper(I) salts, giving alkenes. The corresponding sulphonium salts react more rapidly. Allyic rearrangement cannot be completely avoided.
Chiral Discrimination of Branched-chain Fatty Acids by Reversed-phase HPLC after Labeling with a Chiral Fluorescent Conversion Reagent
作者:Kazuaki AKASAKA、Hiroshi OHRUI
DOI:10.1271/bbb.68.153
日期:2004.1
Anteiso fatty acids having 16 to 29 carbon atoms were labeled with the chiral fluorescent conversion reagents, (1R,2R)- and (1S,2S)-2-(2,3-anthracenedicarboximido)cyclohexanol. The diastereomeric esters of anteiso acids having up to 20 carbon atoms were separated into two peaks in an ODS column under low column-temperature conditions, while those having more than 21 carbon atoms were not separated. A C30 column made it possible to separate diastereomeric esters up to C29 anteiso acid. It was possible to predict the absolute configuration of each acid by the elution order of the derivatives.