Beziehungen zwischen Rotationsisomerie, Wasserstoffbrücken-Bindung und Substituenten-Effekten der organischen Chemie IV

Abstract

Mit Hilfe der Methode der konkurrierenden Wasserstoffbrücken wird an Molekülen wie 2-Hydroxy-5-methyl-3-methylsulfonyl-acetophenon und 2-Hydroxy-5-methyl-3-phenylsulfinyl-aceto-phenon die Fähigkeit der Sulfonyl- und der Sulfinylgruppe, als innermolekulare Protonenakzeptoren zu wirken, untersucht, und es wird gefunden, daß beide Gruppen unter diesen Bedingungen nicht stark sind.Auch die Formyl- und die Carbomethoxygruppe werden als innermolekulare Protonenakzeptoren miteinander verglichen und die Estergruppe als die stärkere erkannt.

Synthesis of functionalized 2-(arylthio)benzoates by formal [3+3] cyclizations of 3-arylthio-1-silyloxy-1,3-butadienes with 3-silyloxy-2-en-1-ones and 1,3-diacylcyclopropanes

“…For example, they are present in dibenzothiophenes, 1 varacins (lissoclinotoxins), 2 lissoclibadins, 3 cyclic sulfides, 4 and various other natural products isolated from Streptomyces griseus. 5 Diaryl sulfides are synthetically available by reaction of arenes with sulfur 6 and sulfur dichloride, 7 by condensation of organometallic reagents with chlorophenyl-sulfide 8 and by base-mediated reaction of chloroarenes with thiophenols. 9 These reactions often suffer from their low regioselectivity and from the formation of polysulfides, due to the harsh reaction conditions.…”

Regioselective Synthesis of 4‐(Arylsulfanyl)‐2‐hydroxyhomophthalates by [4+2] Cycloaddition of 3‐(Arylsulfanyl)‐1‐(trimethylsilyloxy)buta‐1,3‐dienes with Dimethyl Penta‐2,3‐dienedioate

“…Examples include the lissoclibadins, dibenzothiophenes, cyclic sulfides, varacins (lissoclinotoxins), and related natural products [9]. Diaryl sulfides are available by reaction of arenes with sulfur 1 ) or sulfur dichloride [11], by condensation of organometallic reagents with chlorophenylsulfides [12] or by basemediated reactions of thiophenols with chloroarenes [13]. However, the competing formation of polysulfides and, in several cases, the low regioselectivities are severe…”

Synthesis of 5-Arylthio-3-hydroxyphthalates by the First [4+2] Cycloadditions of 3-Arylthio-1-silyloxy-1,3-butadienes with Dimethyl Acetylenedicarboxylate

“…Such compounds include, for example, the lissoclibadins, dibenzothiophenes, cyclic sulfides, varacins (lissoclinotoxins), and related natural products. 1 Diaryl sulfides are available by reaction of arenes with sulfur 2 or sulfur dichloride, 3 by condensation of organometallic reagents with chlorophenylsulfides 4 or by base-mediated reactions of thiophenols with chloroarenes. 5 However, competing formation of polysulfides and (in several cases) the low regioselectivities of the reactions are severe drawbacks of these classic synthetic approaches.…”