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    Total Synthesis of (−)‐Dactylolide
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    Abstract:
    Multiple metals in action: Relying on the prowess of various metal-catalyzed CO and CC bond-forming reactions, a concise asymmetric total synthesis of (−)-dactylolide has been achieved (see scheme). The formation of a Z-trisubstituted vinylboronate through an Alder–ene reaction and subsequent rhenium-mediated regioselective transposition of an allylic alcohol are the key features of this convergent synthesis. Detailed facts of importance to specialist readers are published as "Supporting Information". Such documents are peer-reviewed, but not copy-edited or typeset. They are made available as submitted by the authors. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.
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    Transposition (logic)
    β-Aminoenones react with monoalkyl hydrazines to give regioselectively 1,3,5-trisubstituted pyrazoles. The mechanism and level of regioselectivity depend on both the substitution pattern of the substrates and the reaction conditions. When the least bulky substituent is attached at the β-position of the enone, a high regioselectivity is obtained, usually higher than that from equivalent β-diketones. If the β-substituent is the bulkiest group, the regioselectivity decreases. Nevertheless, in the conditions reported in this paper, it is possible to prepare pyrazoles not obtainable from β-diketones.
    Enone
    Citations (12)
    Attempts to prepare rhenium hexachloride by the method described by Colton (2) have been unsuccessful. The products of the reaction were always impure rhenium oxotetrachloride and rhenium pentachloride. A compound of rhenium(VI), ReOCl 4 OPCl 3 , is shown to have a structure analogous to that of rhenium(V) ions [ReOX 4 .L] − in which the ligands are in a pseudooctahedral arrangement with L trans to the oxo-group (3). Reactions of ReOCl 4 and ReOCl 4 -OPCl 3 with pyridine and 2,2′-dipyridyl are described, and a scheme is proposed for the reactions of the products. Two stable complexes of perrhenyl chloride with the above amines have been obtained.
    Perrhenate
    Citations (22)
    Abstract Allylalkohole (I) werden über die Stufe der Dithiocarbonate in Allylstannane (II) übergeführt und mit m‐Chlorperbenzoesäure zu den isomeren Allylalkoholen (III) oxidativ destannyliert.
    Transposition (logic)
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    Pyrazole is the ubiquitous sub-structure of many natural products and biologically active compounds. In this respect, its regioselective synthesis drew a lot of attention from synthetic organic chemists, leading to the development of various regioselective modifications of the classical Knorr cyclocondensation reaction and alternative methods. This review covers the period of 2003 to the middle of 2009 on the regioselective synthesis of pyrazoles, which are categorized into four reaction types: (i) modified Knorr condensation reaction using 1,3-dicarbonyl surrogates; (ii) 1,3-dipolar cycloadditions approach; (iii) regioselective direct substitution reaction of the pyrazole ring system; and (iv) other methods. Keywords: Pyrazole, regioselective dipolar cycloaddition, regioselective condensation, regioselective cross-coupling
    Pyrazole
    Citations (68)
    We have designed and prepared a series of rhenium complexes with 4,4′-bipyridyl as an electron-accepting unit. Electrochemical studies revealed that oxidation and reduction of these complexes occurred on the rhenium center and the 4,4′-bipyridyl skeleton, respectively. The redox potentials of the rhenium complexes are controllable by tuning the substituents on the 4,4′-bipyridyl skeleton and the coordinating groups to the rhenium center. We have also examined the reactivity of the rhenium complexes in electrochemical and photochemical CO2 reduction.
    Reactivity
    Center (category theory)