Synthese von Ketonsäureäthern aus Aldehyden und Diazoessigäther

Abstract

Ha0 9.84 9.80 9.82 pet. K 21.42 21.21 21.25 B fiir CsClBrO~(OK~+2tIpO I. lI. Ich betrachte es ale meine niichste. Aufgabe, das dritte. miigliche Dichlorchinon darzustellen untl dss Verhalten seines Bromderivata gegen Knlilauge zu studiren. 474. 1 . Buohner und Th. Curtius: Synthere von Ketandlureiithern SUB Aldehyden and Diaxoesai6ll*er. mttheilang atu dem chem. Labor. d. kgL Akademie der Winsendaften zu Miinchen.] (Eingegangen ~J U 14. August.) 1) Diem Berichte XVlI, 956. ' J) Diese Berichte XVII, 954.

A study of the norcaradiene–cycloheptatriene equilibrium in a series of azulenones by NMR spectroscopy; the impact of substitution on the position of equilibrium

“…1 H and 13 C NMR spectra were also recorded in deuterated dichloromethane for VT studies. NMR spectroscopy has enabled rationalisation of the observed trends on the basis of the position and nature of the substituents.…”

“…1,2 Mechanistically, it is believed that this ring expansion occurs via initial carbene addition to provide a norcaradiene 1N followed by reversible 6π electrocyclic ringopening to the more stable cycloheptatriene tautomer ‡ 1T with the equilibrium generally favouring the latter (Scheme 1). 1,2 Mechanistically, it is believed that this ring expansion occurs via initial carbene addition to provide a norcaradiene 1N followed by reversible 6π electrocyclic ringopening to the more stable cycloheptatriene tautomer ‡ 1T with the equilibrium generally favouring the latter (Scheme 1).…”

The interaction of rhodium carbenoids with carbonyl compounds as a method for the synthesis of tetrahydrofurans

“…Reactions of carboalkoxycarbenes with carbonyl compounds were described as early as 1885 [17] and the structures of the dioxolane products were proposed in 1910 [18]. The early investigations by Huisgen and de March [19] with dimethyl diazomalonate (1) revealed that in reactions with benzaldehyde, a mixture of isomeric 1,3-dioxolanes (2) was formed (Scheme 1) when Rh 2 (OAc) 4 , Cu(acac) 2 or CuOTf was used as the catalyst.…”

Iron and Manganese Catalysts for the Selective Functionalization of Arene C(sp2)−H Bonds by Carbene Insertion

“…[4b] Theuse of this strategy onto the aromatic C(sp 2 )ÀHbonds of benzene (Scheme 1B)h as not been developed that much. One of them is the so-called Buchner reaction (Scheme 1C), [5,6] that occurs by formal addition of the carbene unit to the arene C = Cb ond yielding an orcar-adiene which spontaneously opens producing the cycloheptatriene.The opposite transformation, i.e.the retro-Buchner or Echavarren reaction has been described. One of them is the so-called Buchner reaction (Scheme 1C), [5,6] that occurs by formal addition of the carbene unit to the arene C = Cb ond yielding an orcar-adiene which spontaneously opens producing the cycloheptatriene.The opposite transformation, i.e.the retro-Buchner or Echavarren reaction has been described.…”