Palladium-Catalyzed Ring Expansion Reaction of (Z)-1-(1,3-Butadienyl)cyclobutanols with Aryl Iodides. Stereospecific Synthesis of (Z)-2-(3-Aryl-1-propenyl)cyclopentanones
摘要:
A novel type of cascade ring expansion process has been developed by the palladium-catalyzed reaction of (Z)-1-(1,3-butadienyl)cyclobutanols with aryl iodides. The reaction proceeds in a stereospecific manner to produce (Z)-2-(3-aryl-1-propenyl)cyclopentanones. It has also been found that regioselective alpha-arylation of alkenyl cyclopentanones proceeds to afford the alpha-arylated cyclopentanones.
Cascade ring rearrangement of four-membered ring systems containing various propargylic components by a palladium catalyst is described. The reactions of cyclobutanols that have a propargylic carbonate moiety with phenols as nucleophiles produce phenoxy-induced cyclopentanones in high yields. The reactions proceed in a regio- and diastereoselective manner to afford the substituted cyclopentanones with
Strain-Promoted Oxidation of Methylenecyclopropane Derivatives using <i>N</i>-Hydroxyphthalimide and Molecular Oxygen in the Dark
作者:T. E. Anderson、K. A. Woerpel
DOI:10.1021/acs.orglett.0c02075
日期:2020.7.17
The hydroperoxidation of alkylidenecyclopropanes and other strained alkenes using an N-hydroxylamine and molecular oxygen occurred in the absence of catalyst, initiator, or light. The oxidation reaction proceeds through a radical pathway that is initiated by autoxidation of the alkene substrate. The hydroperoxides were converted to their corresponding alcohols and ketones under mild conditions.
Palladium-catalyzed cascade ring expansion reaction of 1-(3-methoxycarbonyloxy-1-propynyl)cyclobutanols with phenols
作者:Masahiro Yoshida、Hideo Nemoto、Masataka Ihara
DOI:10.1016/s0040-4039(99)01749-9
日期:1999.12
opynyl)cyclobutanols to cyclo-pentanones on treatment with phenol derivatives is described. This process can be visualized to proceed via nucleophilicattack to allenyl palladium species by phenol, followed by ring expansion reaction of π-allylpalladiumcomplex to form the corresponding cyclopentanone.
1-bromo-1-ethoxycyclopropane: a new reagent for cyclobutanone synthesis
作者:Robert C. Gadwood
DOI:10.1016/s0040-4039(01)81702-0
日期:1984.1
A variety of of cyclobutanones have been prepared in high yield from 1-bromo-1-ethoxycyclopropane via lithiation, addition to aldehydes or ketones, and mild acid-catalyzedrearrangement of the adducts.
an oxidative ring expansion with Co(acac)2 and triplet oxygen to give 1,2-dioxanols. The formation of an alkoxy radical drives the regioselectivecleavage of the ring on the more substituted side before insertion of molecular oxygen. The reaction is particularly effective on secondary cyclobutanols but works also on certain tertiary alcohols. Further substitution with neutral nucleophiles under catalytic