Synthesis of 4,5-Dihydroisoxazoles by Condensation of Primary Nitro Compounds with Alkenes by Using a Copper/Base Catalytic System
作者:Luca Cecchi、Francesco De Sarlo、Fabrizio Machetti
DOI:10.1002/chem.200800554
日期:2008.9.8
A new procedure for the synthesis of 4.5-dihydroisoxazoles by condensation of primarynitrocompounds with olefins by using a copper/base catalytic system is described. The catalytic effect of copper(II) salts is evidenced by comparison of the reaction rates. Thus, activatednitrocompounds react faster than with organic catalysis by tertiary amines, whereas nitroalkanes, unable to condense with dipolarophiles
Reaction of 2-Isoxazolines with Organolithiums in the Presence of Boron Trifluoride
作者:Hidemitsu Uno、Tetsuya Terakawa、Hitomi Suzuki
DOI:10.1246/bcsj.66.2730
日期:1993.9
In the presence of borontrifluoride, 3,4,5-tri-, 3,5,5-tri and 3,5-disubstituted 2-isoxazolines underwent nucleophilic addition of alkyl- and aryllithiums to give 3,3,4,5-, 3,3,5,5-, and 3,3,5-substituted isoxazolidines in moderate to good yields. On the other hand, in the case of 3,4,5,5-tetrasubstituted isoxazolines, the addition did not proceed at all but proton abstraction took place to afford