Selective
catalytic synthesis of Z-olefins has
been challenging. Here we describe a method to produce 1,2-disubstituted
olefins in high Z selectivity via reductive cross-coupling
of alkyl halides with terminal arylalkynes. The method employs inexpensive
and nontoxic catalyst (iron(II) bromide) and reductant (zinc). The
substrate scope encompasses primary, secondary, and tertiary alkyl
halides, and the reaction tolerates a large number of functional groups.
The utility of the method is demonstrated in the synthesis of several
pharmaceutically relevant molecules. Mechanistic study suggests that
the reaction proceeds through an iron-catalyzed anti-selective carbozincation pathway.
Phthalocyanine compounds of novel type based on a bridged bis-ligand, denoted "intracavity" complexes, have been prepared. Complexation of clamshell ligand 1,1'-[benzene-1,2-diylbis(methanediyloxy)]bis[9(10),16(17),23(24)-tri-tert-butylphthalocyanine] ((clam,tBu)Pc(2)H(4), 1) with lanthanide(III) salts [Ln(acac)(3)]⋅n H(2)O (Ln = Eu, Dy, Lu; acetylacetonate) led to formation of double-deckers (clam,tBu)Pc(2)Ln (2 a-c). Formation of high molecular weight oligophthalocyanine complexes was demonstrated as well. The presence of an intramolecular covalent bridge affecting the relative arrangement of macrocycles was shown to result in specific physicochemical properties. A combination of UV/Vis/NIR and NMR spectroscopy, MALDI-TOF mass-spectrometry, cyclic voltammetry, and spectroelectrochemistry provided unambiguous characterization of the freshly prepared bis-phthalocyanines, and also revealed intrinsic peculiarities in the structure-property relationship, which were supported by theoretical calculations. Unexpected NMR activity of the paramagnetic dysprosium complex 2 b in the neutral π-radical form was observed and examined as well.
Tetra-n-butylammonium
(TBA) (η6-biphenyl)diphenylferrate was formed unexpectedly
in the reaction of (TBA)2[Fe4S4Cl4] with an excess of phenyllithium. This complex belongs to
a novel type of organoferrate.
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