Abstract The aromatic osmacyclopropenefuran bicycles [OsTp{κ 3 ‐C 1 ,C 2 ,O‐(C H C CHC(OEt)O)}(P i Pr )]BF 4 (Tp=hydridotris(1‐pyrazolyl)borate) and [OsH{κ CHC(OEt)O)}(CO)(P ) ]BF , with the metal fragment in a common vertex between fused three‐ five‐membered rings, have been prepared via π‐allene intermediates [OsTp(η ‐CH =CCHCO Et)(OCMe )(P [OsH(η Et)(CO)(OH their aromaticity analyzed by DFT calculations. bicycle containing [OsH(CO)(P ] + is key intermediate [OsH(CO)(OH (P ‐catalyzed...

A catalytic asymmetric direct C–H arylation of (η6-arene)chromium complexes to obtain planar-chiral compounds is reported. The use the hemilabile ligand H8-BINAP(O) key providing high enantioselectivity in this transformation. We show that methodology opens door synthesis a variety chromium derivatives which can be easily transformed into planar chiral mono- or diphosphines. Mechanistic studies, including and characterization Pd Ag their detection reaction mixture, suggest...

Complexes [MCl2(η6-p-cymene)]2 (M = Os (1a), Ru (1b)) react with Li(C5H4CH2CH2NHMe) (LiCpN) and KPF6 to give the sandwich derivatives [M(η5-CpN)(η6-p-cymene)]PF6 (2a), (2b)). Treatment of 2a 2b (2,2′-biphenol)PCl leads [M(η5-CpP)(η6-p-cymene)]PF6 (3a), (3b); CpP C5H4CH2CH2N(Me)P(2,2′-biphenol)). The photolysis 2a, 2b, 3a, 3b in acetonitrile produces release p-cymene group coordination cyclopentadienyl pendant substituent metal center afford [M(η5-C5,κ-N-CpN)(CH3CN)2]PF6 (4a), (4b))...

Significance β-Lactam antibiotics are currently the most broadly used class of antibiotics. These prevent bacterial cell wall from cross-linking, which leads to accumulation long non–cross-linked strands peptidoglycan. Pseudomonas aeruginosa , a nefarious pathogen, attempts repair this aberrantly formed peptidoglycan by function lytic transglycosylase Slt. We document in present report that Slt turns over both scission glycosidic bonds terminus or middle In series seven X-ray crystal...

α-Brominated ketones and aldehydes, with two adjacent electrophilic carbon atoms, are highly valuable synthetic intermediates in organic synthesis, however, their synthesis from unsymmetrical is very challenging, current methods suffer low selectivity. We present a new, reliable, efficient method for the of α-bromocarbonyl compounds excellent yields selectivities. Starting allylic alcohols as carbonyl precursors, combination 1,3-hydrogen shift catalyzed by iridium(III) an bromination gives...

Abstract Proteins with a catalytically inactive LytM-type endopeptidase domain are important regulators of cell wall-degrading enzymes in bacteria. Here, we study their representative DipM, factor promoting division Caulobacter crescentus . We show that the LytM DipM interacts multiple autolysins, including soluble lytic transglycosylases SdpA and SdpB, amidase AmiC putative carboxypeptidase CrbA, stimulates activities AmiC. Its crystal structure reveals conserved groove, which is predicted...

Over the past few decades, numerous model systems have been discovered that create carbon-carbon bonds from CO. These reactions are of potential relevance to Fischer-Tropsch process, a technology converts syngas (H2/CO) into mixtures hydrocarbons. In this paper, homogeneous system constructs carbon chains CO is reported. The exploits cooperative effect transition metal complex and main group reductant. An entire reaction sequence C1 → C2 C3 C4 has synthetically verified. scope reactivity...

Selective reactions that combine H2 , CO and organic electrophiles (aldehyde, ketones, isocyanide) to form hydrogenated C3 C4 carbon chains are reported. These proceed by homologation mediated [W(CO)6 ] an aluminum(I) reductant, followed functionalization hydrogenation of the chain ends. A combination kinetics (rates, KIEs) DFT calculations has been used gain insight into a key step which involves metallocarbene intermediate. findings expand extremely small scope systems make well-defined...

A nice ring: The title compounds are easily prepared by dehydrative cyclization of terminal alkynals in the presence osmium, iridium, and rhodium precursors (see scheme).

A strategy for assembling biaryls linked through a medium-sized ring is herein presented. π-Complexation of fluoroarenes to chromium tricarbonyl activates the molecule towards both C-H activation and nucleophilic aromatic substitution without covalently altering molecular connectivity arene. The construction bridged biaryl molecules with 6-10-membered core rings achieved one-pot arylation/nucleophilic sequence. methodology applicable synthesis heterocyclic as well fully carbocyclic rings.

BglX is a heretofore uncharacterized periplasmic glycoside hydrolase (GH) of the human pathogen

Abstract The aromatic osmacyclopropenefuran bicycles [OsTp{κ 3 ‐C 1 ,C 2 ,O‐(C H C CHC(OEt)O)}(P i Pr )]BF 4 (Tp=hydridotris(1‐pyrazolyl)borate) and [OsH{κ CHC(OEt)O)}(CO)(P ) ]BF , with the metal fragment in a common vertex between fused three‐ five‐membered rings, have been prepared via π‐allene intermediates [OsTp(η ‐CH =CCHCO Et)(OCMe )(P [OsH(η Et)(CO)(OH their aromaticity analyzed by DFT calculations. bicycle containing [OsH(CO)(P ] + is key intermediate [OsH(CO)(OH (P ‐catalyzed...

Natural product bulgecin A potentiates the activity of β-lactam antibiotics by inhibition three lytic transglycosylases in Pseudomonas aeruginosa, which MltD is one. exhibits both endolytic and exolytic reactions turnover cell-wall peptidoglycan tolerates presence or absence stem peptides its substrates. The present study reveals structural features multimodular MltD, presenting a catalytic module four cell-wall-binding LysM modules that account for these attributes. Three X-ray structures...

An active catalytic system for the cross-dehydrogenative coupling (CDC) of a wide range secondary amines with silanes is reported. The iridium(III) derivatives [Ir(H)(X)(κ2-NSiDMQ)(L)] (NSiDMQ = {4,8-dimethylquinoline-2-yloxy}dimethylsilyl; L coe, X Cl, 2; OTf, 3; PCy3, 4; 5), which are stabilized by weak yet noticeable Ir···H–C agostic interaction between iridium and one C–H bonds 8-Me substituent NSiDMQ ligand, have been prepared fully characterized. These species proven to be effective...

The first transition-metal–oxetylidene complex has been prepared by reaction of OsCl(η5-C5H5)(CO)(PiPr3) with 3,3-di(methoxycarbonyl)-5-hexyn-1-al and AgBF4. This novel compound is transformed into a hydroxyalkenylcarbene isomer deprotonation subsequent protonation the resulting α,β-unsaturated acyl transient species. In fluorobenzene at 90 °C, four-membered ring undergoes cycloreversion to afford cis-dicarbonyl derivative cycloalkene.

The complex [Ru(η5-C5H5)(CO)(κ1-OCMe2)(PiPr3)] BF4 (1) reacts with 3,3-bis(methoxycarbonyl)-5-hexyn-1-al to give the α,β-unsaturated cyclopentenylhydroxycarbene derivative [Ru(η5-C5H5){═C(OH)C═CHCH2C(CO2CH3)2CH2}(CO)(PiPr3)]BF4 (2), which undergoes deprotonation Al2O3 afford Ru(η5-C5H5){C(O)C═CHCH2C(CO2CH3)2CH2}(CO) (PiPr3) (3). In presence of P2O5, reaction 1 alkynal leads alkenylvinylidene [Ru(η5-C5H5){═C═C—CH═CH—C(CO2CH3)2—CH2}(CO)(PiPr3)]BF4 (4), yields β,γ-unsaturated...

Ringschluss unter Wasserverlust: Fünf- und sechsgliedrige Ringe sind durch eine einfache dehydratisierende Cyclisierung endständiger Alkinale in Gegenwart von Osmium-, Iridium- oder Rhodium-Vorstufen zugänglich (siehe Schema). Detailed facts of importance to specialist readers are published as ”Supporting Information”. Such documents peer-reviewed, but not copy-edited or typeset. They made available submitted by the authors. Please note: The publisher is responsible for content functionality...

We present herein the application of a lithium anthraquinoid in catalytic synthesis cyclic PLA, showing that aggregation plays critical role <italic>vs.</italic> linear selectivity.

Lytic transglycosylases (LTs) are bacterial enzymes that catalyze the cleavage of glycan strands cell wall. The mechanism this is a remarkable intramolecular transacetalization reaction, accomplished by an ensemble active-site residues. Because LT reaction occurs in parallel with wall bond-forming reactions catalyzed penicillin-binding proteins, simultaneous inhibition both can be particularly bactericidal to Gram-negative bacteria. MltE lytic transglycosylase smallest eight LTs encoded...

Over the past few decades, numerous model systems have been discovered that create carbon–carbon bonds from CO. These reactions are of potential relevance to Fischer-Tropsch (F-T) process, a technology converts syngas mixtures (H2/CO) into hydrocarbons. In this paper, new homogeneous system constructs carbon chains CO is reported. The exploits cooperative effect transition metal complex and main group reductant. An entire reaction sequence C1 C2 C3 C4 has synthetically verified. scope...

Abstract Selective reactions that combine H 2 , CO and organic electrophiles (aldehyde, ketones, isocyanide) to form hydrogenated C 3 4 carbon chains are reported. These proceed by homologation mediated [W(CO) 6 ] an aluminum(I) reductant, followed functionalization hydrogenation of the chain ends. A combination kinetics (rates, KIEs) DFT calculations has been used gain insight into a key step which involves metallocarbene intermediate. findings expand extremely small scope systems make...