SYNTHESIS AND [2+2]-CYCLOREVERSION OF CAGE KETONES
作者:Yoshiro Yamashita、Toshio Mukai
DOI:10.1246/cl.1984.1741
日期:1984.10.5
A series of pentacyclic cageketones 2b-d having no substituent was synthesized by the photochemical [2+2]-cycloaddition reaction of corresponding tricyclic dienones 1b-d. The cageketones 2b-d underwent thermal [2+2]-cycloreversion to give dienones 1b-d. The reactivities were dependent on the length of the bridge “X”.
An insect aggregate pheromone (+)-frontalin and a marine antibiotic (−)-malyngolide, both bearing a quaternary stereogenic center in their molecules, have been synthesized in diastereocontrolled manner by employing a catalytic asymmetric hydrogen transfer reaction as the key step. An inversion protocol allowing enantioconvergent use of the other enantiomeric resolved product has also been devised.
Asymmetric hydrogen transfer protocol for enantiocontrolled synthesis of (−)-chokol G
作者:Regina Mikie Kanada、Kunio Ogasawara
DOI:10.1039/a804343d
日期:——
An enantiocontrolled route to the (â)-chokol G, a fungitoxic metabolite from stromata of Epichloe typhia, has been devised by employing a RuII-catalyzed asymmetric hydrogen transfer reaction as the key step.
Ried, Walter; Bellinger, Oswald, Liebigs Annalen der Chemie, 1984, # 11, p. 1778 - 1784
作者:Ried, Walter、Bellinger, Oswald
DOI:——
日期:——
Lipase-mediated kinetic resolution of tricyclic acyloins, endo-3-hydroxytricyclo[4.2.1.02,5]non-7-en-4-one and endo-3-hydroxytricyclo[4.2.2.02,5]dec-7-en-4-one
Kinetic resolution of tricyclic acyloins, endo-3-hydroxytricyclo[4.2.1.0(2,5)]non-7-en-4-one and endo-3-hydroxytricyclo[4.2.2.0(2,5)]dec-7-en-4-one, and their acetates has been examined using a lipase. It has been found that a facile and stereoselective kinetic resolution occurs both in organic solvent and an aqueous solution in enantiocomplementary ways to afford both enantiomers of the acyloins and their acetates in enantiomerically pure forms. Enantiomerization of (+)-acyloins leading to (-)-acyloin acetates has also been achieved by the same lipase in an organic solvent by addition of a catalytic amount of triethylamine. (C) 1997 Elsevier Science Ltd.