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Upon exposure to a catalytic amount of [RhCl(CO) 2 ] 2 in 1,4-dioxane, homopropargylallene-alkynes underwent a novel cycloisomerization accompanied by the migration of the alkyne moiety of the homopropargyl functional group to produce six/five/five tricyclic compounds in good yields. A plausible mechanism was proposed on the basis of an experiment with 13 C-labeled substrate. The resulting tricyclic derivatives were further converted into the corresponding bicyclo[3.3.0] skeletons with vicinal cis dihydroxy groups., (© 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

For nanobiotechnology to achieve its potential, complex organic-inorganic systems must grow to utilize the sequential functions of multiple biological components. Critical challenges exist: immobilizing enzymes can block substrate-binding sites or prohibit conformational changes, substrate composition can interfere with activity, and multistep reactions risk diffusion of intermediates. As a result, the most complex tethered reaction reported involves only 3 enzymes. Inspired by the oriented immobilization of glycolytic enzymes on the fibrous sheath of mammalian sperm, here we show a complex reaction of 10 enzymes tethered to nanoparticles. Although individual enzyme efficiency was higher in solution, the efficacy of the 10-step pathway measured by conversion of glucose to lactate was significantly higher when tethered. To our knowledge, this is the most complex organic-inorganic system described, and it shows that tethered, multi-step biological pathways can be reconstituted in hybrid systems to carry out functions such as energy production or delivery of molecular cargo., (© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The treatment of benzylallene-substituted internal alkynes with [RhCl(CO)2 ]2 effects a novel cycloisomerization by C(sp(2) )-H bond activation to produce hexahydrophenanthrene derivatives. The reaction likely proceeds through consecutive formation of a rhodabicyclo[4.3.0] intermediate, σ-bond metathesis between the C(sp(2) )-H bond on the benzene ring and the C(sp(2) )-Rh(III) bond, and isomerization between three σ-, π-, and σ-allylrhodium(III) species, which was proposed based on experiments with deuterated substrates., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Treatment of the allene-ene-yne substrates with [{RhCl(CO)2}2] effected the intramolecular [2+2+2]-type ring-closing reaction to produce various of tri- and tetracyclic derivatives containing a cyclopropane ring. The reaction is highly stereoselective as well as stereospecific with good to excellent yields., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

An air-stable cationic Au(I) complex featuring a Z-type ligand (boron atom) as a σ-acceptor was developed for elucidating the effect of B on catalytic reactions. An enyne cyclization in the presence of either [Au→B](+) or [Au](+) showed that [Au→B](+) promotes the reactivity, which enabled the effective construction of not only five- and six-membered rings, but also seven-membered rings., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The efficient Rh(I)-catalyzed cycloisomerization of benzylallene-alkynes produced the tricyclo[9.4.0.0(3,8)]pentadecapentaene skeleton through a C(sp2)-H bond activation in good yields. A plausible reaction mechanism proceeds via oxidative addition of the acetylenic C-H bond to Rh(I), an ene-type cyclization to the vinylidenecarbene-Rh(I) intermediate, and an electrophilic aromatic substitution with the vinylidenecarbene species. It was proposed based on deuteration and competition experiments., (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

A productive channel for pent-up energy: The [{RhCl(CO)2 }2 ]-catalyzed ring-opening of both E and Z 1-cyclopropylocta-1,2,6-trienes exclusively produced cis-4,5-dimethylbicyclo[4.3.0]nona-1(9),2-dienes with three contiguous stereogenic centers. When this transformation was applied to the 1,2,7-triene double-bond isomers, the same products were formed in a completely stereoselective manner., (Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

New tricks, old reactions: The treatment of 2-(1,2-propadienyl)phenylacetonitrile derivatives with a catalytic amount of [{RhCl(CO)dppp}2 ] (dppp=1,3-bis(diphenylphosphanyl)propane) under a CO atmosphere produced benzo[f]oxyindole derivatives. This aza-Pauson-Khand-type reaction was applicable to aliphatic substrates, thus resulting in the formation of the azabicyclo[3.3.0]octadienone derivatives., (Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

No templates needed: The title reaction makes it easy to construct the bicyclo[6.3.0]undecadienone framework in high yields (see scheme). A template effect is not required to achieve this ring-closing reaction efficiently. The present method can be applied to the construction of bicyclo[5.3.0] and bicyclo[4.3.0] ring systems. Ts = p-toluenesulfonyl.