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

Short Enantioselective Formal Synthesis of (–)-Platencin

A short enantioselective formal synthesis of the antibiotic natural product platencin is reported. Key steps in the synthesis include enantioselective decarboxylation alkylation, aldehyde/olefin radical cyclization, and regioselective aldol cyclization

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

Iridium-Catalyzed Asymmetric Intramolecular Allylic Amidation:Enantioselective Synthesis of Chiral Tetrahydroisoquinolines and Saturated Nitrogen Heterocycles

For the first time iridium catalysis has been used for the synthesis of chiral tetrahydroisoquinolines with excellent yields and high enantioselectivities (see scheme; cod=1,5-cyclooctadiene, DBU=1,8-diazabicyclo[5.4.0]undec-7-ene). These products are important chiral building blocks for the synthesis of biologically active compounds, in particular alkaloids

Chain walking of allylrhodium species towards esters during rhodium-catalyzed nucleophilic allylations of imines

Allylrhodium species derived from δ-trifluoroboryl β,γ-unsaturated esters undergo chain walking towards the ester moiety.The resulting allylrhodium species react with imines to give products containing two new stereocenters and a Z-alkene. By using a chiral diene ligand, products can be obtained with high enantioselectivities, where a pronounced matched/mismatched effect with the chirality of the allyltrifluoroborate is evident

Enantioselective rhodium-catalyzed coupling of arylboronic acids, 1,3-enynes, and Imines by alkenyl-to-allyl 1,4-rhodium(I) migration

A chiral rhodium complex catalyzes the highly enantioselective coupling of arylboronic acids, 1,3-enynes, and imines to give homoallylic sulfamates. The key step is the generation of allylrhodium(I) species by alkenyl-to-allyl 1,4-rhodium(I) migration

The Isomerization of Allylrhodium Intermediates in the Rhodium-Catalyzed Nucleophilic Allylation of Cyclic Imines

Allylrhodium species generated from potassium allyltrifluoroborates can undergo isomerization by 1,4-rhodium(I) migration to give more complex isomers, which then react with cyclic imines to provide products with up to three new stereochemical elements. High enantioselectivities are obtained using chiral diene–rhodium complexes

Arylative intramolecular allylation of ketones with 1,3-enynes enabled by catalytic alkenyl-to-allyl 1,4-Rh(I) migration

Alkenyl-to-allyl 1,4-Rh(I) migration enables the generation of nucleophilic allylrhodium(I) species by remote C–H activation. This new mode of reactivity was employed in the diastereoselective reaction of arylboron reagents with substrates containing a 1,3-enyne tethered to a ketone, to give products containing three contiguous stereocenters. The products can be obtained in high enantioselectivities using a chiral sulfur–alkene ligand