The structures of the components in the triethylborane-mediated radical addition reaction of oxime ether were investigated by 1H- and 3D-DOSY NMR methods. It has been impossible to physically separate the unstable intermediates; therefore, the structures were thus far unidentified. It has been possible to elucidate the structures of these unstable intermediates using Diffusion-Ordered Spectroscopy (DOSY) methods for the reaction in an NMR tube. The DOSY methods resolved the spectra of each starting compound, intermediate and product having different diffusion coefficients. The structure of the intermediate was shown to be due to the bonding of diethylborane to the nitrogen atom of the alkoxyamino group.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1002/mrc.1847 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Reaction of cyclopropenes with a trichloromethyl radical: unprecedented ring-opening reaction of cyclopropanes with migration.
Chem Commun (Camb)
March 2015
Kobe Pharmaceutical University, Motoyamakita, Higashinada, Kobe 658-8558, Japan.
The direct addition reaction of chloroform to cyclopropenes under triethylborane-mediated radical reaction conditions to provide trichloromethylcyclopropanes has been developed. In contrast, using dimethylzinc as a radical initiator led to the formation of unconjugated esters via a domino sequence involving the addition of the trichloromethyl radical, rearrangement and ring-opening reactions.
View Article and Find Full Text PDFRadical addition-initiated domino reactions of conjugated oxime ethers.
Chem Pharm Bull (Tokyo)
May 2015
Article Synopsis
- The text discusses the use of conjugated oxime ethers in creating complex chemical structures through domino radical reactions.
- The triethylborane-mediated reactions enable the formation of carbon-sulfur and carbon-oxygen bonds efficiently, leading to β-hydroxy sulfides and other products.
- Investigations into the radical addition and aldol-type reactions have revealed new pathways, including the synthesis of γ-butyrolactone and benzofuro[2,3-b]pyrrol-2-ones through a series of radical and rearrangement processes.
High performance of N-alkoxycarbonyl-imines in triethylborane-mediated tin-free radical addition.
J Org Chem
February 2012
Graduate School of Pharmaceutical Sciences, Kyoto University, Yoshida, Kyoto 606-8501, Japan.
Triethylborane-mediated tin-free radical alkylation of N-alkoxycarbonyl-imines, such as N-Boc-, N-Cbz-, and N-Teoc-imines, proceeded smoothly at a low temperature (-78 to -20 °C) to give the corresponding adducts in high yield. Although the formation of isocyanate was the major unfavorable reaction at room temperature, a one-pot conversion of N-Boc-imine to N-ethoxycarbonyl-adduct was possible through the corresponding isocyanate generated in situ. The higher performance of N-alkoxycarbonyl-imine than those of N-Ts- and N-PMP-imines is rationalized by a moderate electron-withdrawing character of an alkoxycarbonyl group that makes both addition of alkyl radical and trapping of the resulting aminyl radical by triethylborane efficiently fast.
View Article and Find Full Text PDFAerobic hydroxylation of N-borylenamine: triethylborane-mediated hydroxyalkylation of alpha,beta-unsaturated oxime ether.
Org Lett
October 2009
Kobe Pharmaceutical University, Motoyamakita, Higashinada, Kobe 658-8558, Japan.
Intermolecular hydroxyalkylation of alpha,beta-unsaturated imines involving Et3B-mediated regioselective alkyl radical addition and subsequent hydroxylation with molecular oxygen has been developed, in which N-borylenamine generated by trapping of the enaminyl radical with Et3B was a key intermediate in the proposed aerobic hydroxylation mechanism.
View Article and Find Full Text PDFStructure elucidation of the intermediate in triethylborane-mediated radical addition of oxime ethers with 2D- and 3D-DOSY NMR.
Magn Reson Chem
August 2006
Chemical Analysis Center, Yokohama National University, 79-5 Tokiwadai, Hodogaya-ku, Yokohama, 240-8501, Japan.
The structures of the components in the triethylborane-mediated radical addition reaction of oxime ether were investigated by 1H- and 3D-DOSY NMR methods. It has been impossible to physically separate the unstable intermediates; therefore, the structures were thus far unidentified. It has been possible to elucidate the structures of these unstable intermediates using Diffusion-Ordered Spectroscopy (DOSY) methods for the reaction in an NMR tube.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!