Chiral P,S-Ligands Based on β-d-Thioglucose Tetraacetate. Palladium(II) Complexes and Allylic Alkylation

Abstract

The new chelating P,S-ligands 2,3,4,6-tetra-O-acetyl-1-((2-(diphenylphosphino)benzy)lthio)-β-d-glucopyranose, [(2-Ph2PC6H4CH2)SCHCH(OAc)CH(OAc)CH(OAc)CH(CH2OAc)O, 2] and 2,3,4,6-tetra-O-acetyl-1-((2-(dicyclohexylphosphino)benzyl)thio)-β-d-glucopyranose [(2-Cy2PC6H4CH2)SCHCH(OAc)CH(OAc)CH(OAc)CH(CH2OAc)O,, 3] as well as their (1,3-diphenylallyl)palladium(II) cationic complexes [Pd(η3-PhCHCHCHPh)(2)]PF6, 6, and [Pd(η3-PhCHCHCHPh)(3)]PF6, 7, and one η3-C3H5 complex [Pd(η3-C3H5)(2)]PF6, 5, have been prepared. The solid-state structure of [Pd(η3-C3H5)(2)]PF6, 5, has been determined by X-ray diffraction methods and found to have the S-sugar substituent and one of the P-phenyl rings in pseudo-axial positions on the same side of the P−Pd−S coordination plane. Detailed NMR measurements for 6 reveal the presence of two diastereomeric isomers whereas for 7 four diastereomers are found. 2-D exchange NMR is used to characterize several of the selective equilibria within 6 and 7. On the basis of the observed ee in the enantioselective homogeneous allylic alkylation of 7, it is suggested that the reaction kinetics for the four isomers are not all the same.

An Unexpectedly Stable Chiral Hydrido‐Solvent Complex of RuII: A mechanistic link in the enantioselective hydrogenation of pyrones. Preliminary communication

“…3,b. The 3-D solution structure of 3 has been determined using 'H-ROESY (and not NOESY) measurements, in combination with our usual methodology [9], and will be described subsequently. Since 2 has coordinated i-PrOH solvent molecules, we attempted and succeeded in preparing the bis-acetone complex [Ru(OAc)(acetone),(l)]BF, (4).…”

“…3,b. The 3-D solution structure of 3 has been determined using 'H-ROESY (and not NOESY) measurements, in combination with our usual methodology [9], and will be described subsequently. 7.0 6.5 6.0 Fig.…”

Cationic Iridium Complexes with Chiral Dithioether Ligands: Synthesis, Characterisation and Reactivity under Hydrogenation Conditions

“…[1,2] In particular, complexes containing thioether mixed-donor ligands such as the P,S-, [3][4][5][6][7][8] N,S- [9][10][11][12][13][14][15][16][17] and O,S- [18][19][20][21][22] donors have been successfully applied in asymmetric hydrogenation, [5,6,23] allylic substitutions [7][8][9][10]18] and enantioselective hydrosilylation of ketones. [4,23] In contrast, catalysts with chiral bidentate thioether ligands have been scarcely investigated, [24][25][26][27][28][29][30][31][32] although some have shown promising catalytic properties.…”

Use of Beds in The Event of a Scabies Infection in Boarding Schools

“…A few days later, these eggs hatch to produce young mites (larvae). Infection from scabies can cause severe itching, which is an allergic reaction to mites (Mading & Indriaty, 2015). Mites live in the epidermis, are resistant to water and soap, and remain alive even after bathing with hot water every time (Indonesian Medical Association, 2017).…”