Disulfoxide Ligands in Rhodium Catalyzed Asymmetric 1,4-Addition: First Studies and Future Directions

Disulfoxides with atropisomeric backbones are introduced as readily available chiral ligands for the rhodium-catalyzed 1,4-addition of arylboronic acids to unsaturated carbonyl compounds. The ligands are obtained in pure form from either commercially available or easily synthesized starting materials. Precatalysts with general formula {(disulfoxide)RhCl}2 were prepared in high yield and were fully characterized. Preliminary results on the influence of steric and electronic modifications of the ligand structure and their impact on the catalytic behavior are presented

Vnímání, kauzalita a pozornost Roger Bacon a Petr Olivi

[Sensation, Causality, and Attention: Roger Bacon and Peter Olivi] This paper investigates what conditions are to be met for sensory perception to occur. It introduces two diff erent theories of perception that were held by two medieval Franciscan thinkers — namely, Roger Bacon (1214/1220–1292) and Peter Olivi (ca. 1248–1298). Bacon analyses especially the causal relation between the object and the sensory organ in his doctrine of the multiplication of species. In his view, a necessary condition of perception is the reception of the species in a fully disposed sensory organ. On the contrary, Olivi stresses the active role of the sensory power. A necessary condition of sensation is the aspectus — i.e. the focus of our power’s attention on the object. Furthermore, the paper investigates whether and how each of the two thinkers can deal with the arguments proposed by his opponent — namely whether Bacon’s theory is able to explain attention and what the causal role of the object in Olivi’s theory is

The effect of substituents on the syn-anti conformer ratio in naphthyl-based imidazolinium salts and their corresponding N-heterocyclic carbenes

Eight new N-heterocyclic carbenes (NHCs) featuring substituted naphthyl side chains were synthesized. These molecules are present in solution as a stable mixture of antiand synconformers. Through careful tuning of the substituents on position 2 and 2,7 of the naphthyl moieties, it was possible to synthesize molecules that display a strong preference for the anticonformation (up to 95:5). This will greatly facilitate their optimized use as single isomeric ligands in metal-catalysis and as organocatalysts

An optically pure P-alkene-ligated Ir(I) complex

The asymmetric unit of (P)-chloridobis[(S)-(+)-5-(3,5-dioxa-4-phosphacyclo­hepta­[2,1-a:3,4-a']dinaphthalen-4-yl)dibenz[b,f]azepine]iridium(I)-benzene-pentane (1/1/1), [IrCl(C34H22NO2P)2]·C6H6·C5H12, contains two formula units. The two symmetry-independent mol­ecules of the Ir complex have similar conformations and approximate C2 symmetry, with small deviations arising from slightly different puckering of the seven-membered di­oxa­phospha­cyclo­hepta­di­ene rings. The Ir atoms have trigonal-bipyramidal coordination geometry, with the P atoms in axial positions. The steric strain of the bidentate coordination of the P-alkene ligand through its P and alkene C atoms causes the N atom to have pyramidal geometry, compared with the trigonal-planar geometry observed in the free ligand. The coordination also results in an anti conformation of the binaphthyl and alkene groups within the P-alkene ligand

Chiral Phosphorus–Olefin Ligands for the RhI‐Catalyzed Asymmetric Addition of Aryl Boronic Acids to Electron‐Deficient Olefins

New chiral phosphorus–olefin hybrid ligands derived from the rigid “privileged” l‐proline have been conveniently prepared and applied in the rhodium‐catalyzed asymmetric arylation of electron‐deficient olefins with arylboronic acids at room temperature; this reaction provides the desired products in excellent yields and high enantioselectivities. The origin of observed stereoselectivity has been investigated by density functional theory (DFT) calculations.New chiral phosphorus–olefin hybrid ligands derived from l‐proline have been conveniently prepared and applied in the rhodium‐catalyzed asymmetric arylation of electron‐deficient olefins with arylboronic acids at room temperature. This reaction provides the desired products in excellent yields with high enantioselectivity. The origin of observed stereoselectivity has been investigated by density functional theory (DFT) calculations.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/137195/1/asia201600143.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/137195/2/asia201600143-sup-0001-misc_information.pd

Synthesis of 3-fluoro-3-aryl oxindoles: Direct enantioselective α arylation of amides

Modus operandi: Catalytic access to the title compounds through a new asymmetric α-arylation protocol is reported (see scheme). These products are formed in good yields and excellent enantioselectivities by using a new and easily synthesized chiral N-heterocyclic carbene (NHC) ligand. Advanced DFT calculations reveal the properties of the NHC ligand and the mode of operation of the catalyst. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

Room-temperature synthesis of tetra-ortho-Substituted biaryls by NHC-catalyzed Suzuki-Miyaura couplings

Into the groove: The introduction of a C2‐symmetric N‐heterocyclic carbene ligand with appropriately substituted naphthyl side chains enables the efficient Suzuki–Miyaura coupling to form bulky tetra‐ortho‐substituted biaryls from aryl bromides and chlorides at room temperature. DFT calculations uncover the subtle steric phenomena at play that lead to the superior catalytic performance. Cyoct=cyclooctyl