Tandem Nucleophilic Addition/Oxy-2-azonia-Cope Rearrangement for the Formation of Homoallylic Amides and Lactams: Total Synthesis and Structural Verification of Motuporamine G
作者:Lijun Zhou、Zhiming Li、Yue Zou、Quanrui Wang、Italo A. Sanhueza、Franziska Schoenebeck、Andreas Goeke
DOI:10.1021/ja310002m
日期:2012.12.12
oxy-2-azonia-Cope rearrangements give homoallylic amides. In the case of 2-vinylcycloalkanones, the process results in ring enlargement, providing a novel route to 9- to 16-membered lactams. The preparative significance of this protocol was evidenced by a short synthesis of macrocyclic alkaloid motuporamine G. The stereochemistry-defining step of this oxy-azonia-Cope rearrangement was further studied
Electroreductive intermolecular coupling of ketones with O-methyl oximes. A convenient route to synthesis of 2-amino alcohols
作者:Tatsuya Shono、Naoki Kise、Taku Fujimoto
DOI:10.1016/s0040-4039(00)79486-x
日期:1991.1
The electroreduction of ketones together with O-methyl oximes gave intermolecularly coupled products, 2-methoxyamino alcohols, which were easily reduced to 2-amino alcohols.
Process for preparing N,O-dialkylhydroxylamine, its salts or
申请人:Mitsui Petrochemical Industries, Ltd.
公开号:US05510511A1
公开(公告)日:1996-04-23
A process for preparing N,O-dialkylhydroxycarbamic acid ester which comprises reacting hydroxylamine or its salt with dihydrocarbyl carbonate in the presence of a basic compound to prepare hydroxycarbamic acid ester and subsequently alkylating this compound with an alkylating agent; a process for recovering N,O-dialkylhydroxycarbamic acid ester which comprises azeotropically distilling the ester with water from a solution containing the ester; a process for preparing N,O-dialkylhydroxylamine which comprises hydrolyzing N,O-dialkylhydroxycarbamic acid ester in an aqueous solution or a hydrous solvent in the presence of an alkali; a process for purifying N,O-dialkylhydroxylamine hydrochloride which comprises adding aldehyde or ketone to a solution of N,O-dialkylhydroxylamine hydrochloride containing O-alkylhydroxylamine hydrochloride as impurities to convert the O-alkylhydroxylamine hydrochloride into O-alkyl aldoxime or O-alkyl ketoxime and subsequently separating the N,O-dialkylhydroxylamine hydrochloride from the reaction system; and a process for separating N,O-dialkylhydroxylamine hydrochloride which comprises (i) adding benzene or alkylated benzene to an aqueous solution containing N,O-dialkylhydroxylamine hydrochloride, azeotropically removing water or a hydrochloride solution, and, subsequently (ii)adding alcohol thereto to obtain N,O-dialkylhydroxylamine hydrochloride in the form of crystal.
Removable Silyl Group as a “Masked Proton” in Oxy-2-oxonia(azonia)-Cope Rearrangement: Applications in Stereoselective Total Synthesis of Natural Macrolides
In the presence of a Lewis acid, trimethylsilyl-substituted β,γ-unsaturated ketones and aldehydes (imines) undergo nucleophilic addition to produce zwitterionic intermediates, followed by oxy-2-oxonia(azonia)-Cope rearrangements to give homoallylic esters (amides). In the case of TMS-containing 2-vinylcycloalkanones, the process results in ring-enlargement, providing 10- to 16-membered lactones. This
Disclosed is a direct acid catalyzed intermolecular electrocyclic rearrangement process for the preparation of linear and cyclic homoallylic ester and amides.