A simple, stereoselective, room-temperature synthesis of cis vinyloxiranes and trans 1-phenyl-1,3-butadiene
作者:Jacques Auge、Serge David
DOI:10.1016/s0040-4039(00)88249-0
日期:1983.1
The organotin reagent from 1-chloro-3-iodoprop-1-ene and SnCl2 in dimethylformamide reacted with aldehydes by ite chlorine-substituted carbon atom. Treatment with NaOMe then gave vinyloxiranes with good stereo-selectivity. benzaldehyde and 1-bromo-3-iodoprop-1-ene in the presence of two equivalents of SnCl2 gave exclusively -1-phenyl-1,3-butadiene.
THE HIGHLY STEREOSELECTIVE SYNTHESIS OF<i>CIS</i>-VINYLOXIRANES
作者:Masahiko Yamaguchi、Teruaki Mukaiyama
DOI:10.1246/cl.1982.237
日期:1982.2.5
In the presence of triethylaluminum, oxyallyl anions derived from 2-allyloxybenzimidazoles react with aldehydes in highly regio-and stereoselective manner to afford α-adducts in good yields. The adducts are stereospecifically converted to cis-vinyloxiranes in good yields.
Cyclopropyl carbinol derivatives were efficiently prepared through a highly diastereoselective hydrozirconation of vinyloxirones and the intramolecular nucleophilic attack of the generated alkylzirconocene with the inversion of the configuration at the reacting oxirane carbon.
Cyclopentyl and cyclopropylmethanol derivatives were efficiently prepared through a chemoselective hydrozirconation reaction of (1-butenyl)oxirane and vinyloxirane with Cp2ZrHCl. However, the attemped reaction of (1-pentenyl)oxirane or (1-propenyl)oxirane failed to yield cyclohexyl or cyclobutylmethanols. The ring formation was stereospecific and proceeded with the inversion of the configuration at the reacting oxirane carbon. The origin of stereospecificity and the stereoselectivity in the formation of cyclopropylmethanols was presumed by the approach of the Schwartz reagent from the less hindered site of the stable gauche-conformer of the vinyloxirane compound in the transition state. (Cyclopropylmethyl)amine derivatives were also prepared by the treatment of vinylaziridine derivatives with Cp2ZrHCl. (C) 1997 Elsevier Science Ltd. All rights reserved.