Aus den Trimethylsilyloxy-allylchloride (I), (V), (IX) werden mit AgClO4 entsprechende Silyloxy-allyl-Kationen, zB (XIII) [aus (Ia)], erzeugt, die in Nitromethan zB mit Furan (II) under Bildung der Addukte (III)+(IV) bzw。(VI) [neben (VIb)-(VIe) auch die Isomeren (VII) bzw. (八)】bzw。(X) [neben (Xb), (Xc) auch die Isomeren (XI) bzw. (XII)]反应器(Diskussion des Reaktionsmechanismus)。
The favorskii rearrangement of dichlorinated methylketones
作者:N. Schamp、N. De Kimpe、W. Coppens
DOI:10.1016/0040-4020(75)80198-0
日期:1975.1
Twenty-two dichlorinated methylketones have been submitted to Favorskiirearrangement in NaOMeMeOH. Distribution of products is strongly dependent on substitution. Primary dichloromethyl-ketones (R2 = H) gave rise to Favorskii esters only. Results are explained by a cyclopropanone intermediate, which is formed stereospecifically by disrotative closure of a delocalized zwitter-ion. Opening of the cyclopropanone
A new method for N-acryloylation of Evans’ chiral auxiliaries (oxazolidin-2-ones) with α,α′-dichloro ketones in the presence of the electrogenerated base 2-pyrrolidone anion is described. N-Enoyloxazolidin-2-ones are obtained, under mild reaction conditions, in good to high yields.