Reaktionen mit Phosphin‐alkylenen, III ¹⁾ Über die Wittig‐Reaktion mit Tricyclohexylphosphin‐alkylenen

Abstract

Tricyclohexylphosphin-alkylene vermagen die Wittig-Reaktion einzugehen, wobei die Olefinbildung durch resonanzstabilisierende Gruppen am Ylid b e a nstigt wird. In den untersuchten Beispielen wurden nur mns-Olefine erhalten.Filr den stereoselektiven Reaktionsablauf wird eine Deutung gegeben.

The behavior of 2-substituted-1,3-diphenylpropane-1,3-tione toward organophosphorus reagents

“…Benzene (thiophene-free) and petroleum ether (boling range 60-80 ЊC) were dried with sodium. Wittig reagents 2a-e were prepared according to established procedures [20][21][22]. The trialkyl phosphites were prepared according to established procedures and were purified by treatment with sodium followed by fractional distillation [23,24].…”

Chemistry of Phosphorus Ylides, Part 30. Reaction of Camphorquinone Derivatives with Active Phosphacumulenes and Stabilized Phosphonium Ylides

“…A mixture of 1 (0.16g, 0.001 mol) and methoxycarbonyl methylenetriphenyl phosphorane (6a) (29) (0.67g, 0.002 mol) was boiled in dry toluene (30 ml) for 8hr. The solvent was distilled off and the residue was chromatographed on silica gel using pet.…”

“…Camphorquinonephenylhydrazone (13) (0.26g, 0.001 mol) was added to a solution of methoxycarbonyl-(6a) (29) (0.33g, 0.001 mol) or ethoxycarbonylmethylenetriphenylphospho-rane (6b) (29) (0.34g, 0.001 mol) in dry toluene (30ml ), and the reaction mixture was refluxed for 10hr in case of 6a and 12hr when 6b was used. The solvent was distilled off under reduced pressure; the residue was applied to silica gel column chromatography to afford compounds 15a and 15b, respectively.…”

Organophosphorus chemistry 30 [1]. The behavior of 4-hydroxycoumarin toward methylenetriphenylphosphoranes (Wittig Reagents) and alkyl phosphites

“…A mixture of 1 (0.8 g, 0.01 mol) and benzoylmethylenetriphenylphosphorane 2a [21] (2.1 g, 0.011 mol) in toluene (50 mL) was refluxed for 30 hours. The reaction mixture was evaporated to dryness in the presence of silica gel (5 g).…”