Asymmetric Synthesis of Bioactive Hydrodibenzofuran Alkaloids: (−)-Lycoramine, (−)-Galanthamine, and (+)-Lunarine
作者:Peng Chen、Xu Bao、Le-Fen Zhang、Ming Ding、Xiao-Jie Han、Jing Li、Guo-Biao Zhang、Yong-Qiang Tu、Chun-An Fan
DOI:10.1002/anie.201103198
日期:2011.8.22
Divergent route: A direct CC bond‐forming approach to the key aryl‐substituted all‐carbon quaternary stereogenic center present in bioactive hydrodibenzofuran alkaloids has been discovered. This approach involves an unprecedented organocatalyticenantioselectiveMichaeladdition of α‐cyanoketones with acrylates (see scheme) and was used in a novel and divergent synthetic strategy for the title compounds
A catalytic enantioselective synthetic strategy for the aryl-substituted all-carbon quaternary stereocenters of bioactive hydrodibenzofuran alkaloids was achieved by the Michael addition reaction of α-cyano ketones and acrylates using a chiral tertiary amine–thiourea catalyst. This method can tolerate steric bulkiness and multiple functional groups, and 32 Michael adducts were prepared in good to excellent
The use of a particulate polymer as a carrier for biological substances and the like and such substances supported on the carrier
申请人:JAPAN SYNTHETIC RUBBER CO., LTD.
公开号:EP0095932A1
公开(公告)日:1983-12-07
A carrier particularly suitable for supporting biological substances is composed of a particulate polymer prepared by polymerizing at least one monomer of formula:
(in which R1 and R2 are the same or different and each represents a hydrogen atom or an alkyl group, R3 represents a straight or branched chain alkylene group optionally having a hydroxy substituent, X represents a halogen atom, m is 0 or an integer from 1 to 10 and n is an integer from 1 to 5) optionally in admixture with at least one other copolymerizable monomer. Biological substances which may be supported by the carrier include immunoreactive substances, enzymes, cells and cell-discriminating substances.
Cat. on a hot tin roof: Enantioselective catalytic Michael addition of α-cyanoketones to acrylates under bifunctional organocatalysis was used to construct the unique arylic all-carbon quaternary stereocenter, which is synthetically crucial in the chemical synthesis of optically pure cis-aryl hydroindole alkaloids. The protocol offers an asymmetric route to (+)-vittatine, (+)-epi-vittatine, and (+)-buphanisine.
Ruthenium(II)biscarboxylate‐Catalyzed Hydrogen‐Isotope Exchange by Alkene C−H Activation
作者:Alexander Bechtoldt、Lutz Ackermann
DOI:10.1002/cctc.201801601
日期:2019.1.9
biscarboxylate catalysis enabled efficient hydrogen isotope exchange of acrylic C−H bonds with user‐friendly D2O. The C−H labelling was characterized by excellent positional selectivity and a broad functional group tolerance. The deuteration was successfully conducted on 55 mmol scale with TONs of >1000, while mechanistic studies provided insights into ruthenium(II) oxidase catalysis. The obtained deuterated