Polyethylene Oxides as Organic Reactions Activators II.¹An Easy Generation of Dihalocarbenes

Syntheses ofgem-Dihalocyclopropanes and Their Use in Organic Synthesis

“…147 Suitably substituted vinyl ketones, especially those with an alkyl group in the R position, undergo addition of dichlorocarbene under PTC conditions; however, the yields are often low, as shown, for example, in eq 30. 148 It seems that Seyferth's method should be a good choice for synthesizing the addition products of dichlorocarbene and vinyl ketones in high yields. Unfortunately, there are only a few examples of reactions of these compounds with dichlorocarbene generated from trichloromethyl(phenyl)mercury.…”

“…Suitably substituted vinyl ketones, especially those with an alkyl group in the α position, undergo addition of dichlorocarbene under PTC conditions; however, the yields are often low, as shown, for example, in eq 30 …”

Phase-Transfer Catalysis Reaction with Strong Bases

“…A systematic study of the reactivity of this reaction by Dehmlow and Lissel showed that Et4N bromide, cetylNMe3 bromide, and cetylPBu3 bromide gave similar reactivities and 18crown-6 and Ph 4 P+CI-gave even higher reactivity [213]. The use of PEG in the presence of powdered KOH for 3 h at O°C to room temperature gave 100% conversion (93% isolated yield) in this reaction [214]. The use of PEG in the presence of powdered KOH for 3 h at O°C to room temperature gave 100% conversion (93% isolated yield) in this reaction [214].…”