202061-77-6Relevant academic research and scientific papers
One-pot synthesis of five- or six-membered carbocycles through intramolecular cycloadditions by the use of ethyl chloroformate
Liu, Ju-Tsung,Lin, Wen-Wei,Jang, Jeong-Jiunn,Liu, Jing-Yuan,Yan, Ming-Chung,Hung, Chihua,Kao, Kuo-Hsi,Wang, Yeh,Yao, Ching-Fa
, p. 7115 - 7128 (2007/10/03)
The Michael addition reactions of β-nitrostyrenes 1 with 4-pentene-1- magnesium bromide 2a or 3-butene-1-magnesium bromide 2b generated nitronates 3 or 4. Medium to high yields of isoxazolidine derivatives 9 and 10 were obtained when nitronates 3 or 4 were treated with ethyl chloroformate and catalytic amount of 4-dimethylaminopyridine (DMAP) at room temperature in one-pot and the ratios of trans-9:cis-9 were from 1:3.00 to 1:4.06 and the ratios of trans-10:cis-1 0 were >99:1. The formation of compounds 9 is proposed to proceed through intramolecular nitrile oxide-olefin cycloadditions (INOC) because compounds 14a-d, obtained from the trapping of the nitrile oxides by ethyl chloroformate, could be isolated. The mechanism of the generation of compounds 10 is proposed to proceed through intramolecular alkoxycarbonyl nitronate-olefin cycloadditions (IAOC) to form intermediates N-(ethoxycarbonyl)isoxazolidines 13 and then eliminate EtOH and CO2 (or EtOCO2H) to yield the final products.
Generation of nitroalkanes, hydroximoyl halides and nitrile oxides from the reactions of β-nitrostyrenes with Grignard or organolithium reagents
Yao, Ching-Fa,Kao, Kuo-Hsi,Liu, Ju-Tsung,Chu, Cheng-Ming,Wang, Yeh,Chen, Wen-Chang,Lin, Yu-Mei,Lin, Wen-Wei,Yan, Ming-Chung,Liu, Jing-Yuan,Chuang, Ming-Ching,Shiue, Jin-Lien
, p. 791 - 822 (2007/10/03)
The β-nitrostyrenes 1 or 2 react with Grignard or organolithium reagents in ether or THF solution to generate by 1,4-addition the intermediate nitronates A. When A is treated with dilute hydrochloric acid, high yields of the nitroalkanes 3 (and oximes 4) or 5 are obtained Hydroximoyl halides 6, 8 or nitrile oxides 7 can be isolated when the intermediate A is slowly added to the ice cold concentrated hydrohalic acid. The same products 6 and/or 7 are observed if the nitronates, generated from the substrate 1a, are added to 85% aqueous H2SO4 but only the hydrolyzed carboxylic acids 9 are generated when the β-nitrostyrenes 2 are reacted with Grignard reagents and worked up under the same condition. The nitrile oxides 7 can undergo 1,3-dipolar cycloaddition with alkenes or alkynes to generate 2-isoxazolines or isoxazoles. A one-pot synthesis of the [n,3,0] bicyclic (n = 3 or 4) compounds 23-27 by intramolecular nitrile oxide-olefin cycloadditions is reported.
