反应详情

Addition of 1-chloro-1-octyne to 1.5 equivalents of sodium trimethylaluminum hydride in diglyme at 0° C. with stirring for one hour resulted in the regio- and stereoselective formation of the E-alpha-chloroalkenylalanate, [HexHC=C(Cl)AlMe3 ]-Na+, in 89% yield as evidenced from 1H-NMR (the vinylic proton was present as a triplet, J=8 Hz, at 5.88 ppm) and gas chromatography (GC) analysis of the trans-1-chloro-1-octene obtained upon protonolysis. None of the corresponding cis-1-chloro-1-octene was observed by a gas chromatography comparison with an authentic sample. In addition, 11% of 1-octyne was found by gas chromatography. Allowing the reaction mixture to warm to room temperature and stirring for two hours produced by gas chromatography analysis cis-2-nonene (17%) with no trans-1-chloro-1-octene remaining. Hence, the migratory insertion reaction of the foregoing alpha-chloroalkenylalanate to form the vinylalane, HexHC=C(Me)AlMe2, did occur.

1. customresulted in the regio- and stereoselective formation of the E-alpha-chloroalkenylalanate, [HexHC=C(Cl)AlMe3 ]-Na+, in 89% yield
2. customobtained upon protonolysis
3. stirringstirring for two hours