New Potentially Chelating Chiral Magnesium Amide Bases for Use in Enantioselective Deprotonation Reactions

Abstract

All reagents and solvents were obtained from commercial suppliers and were used without further purification unless otherwise stated. Purification was carried out according to standard laboratory methods. 1 Tetrahydrofuran and diethyl ether were dried by heating to reflux over sodium wire, using benzophenone ketyl as an indicator, then distilled under nitrogen. Diethyl ether (for purification purposes) and petroleum ether 30-40 °C were used as obtained from suppliers without further purification. Din -butylmagnesium, n-Bu 2 Mg, 2 obtained as a 1M solution in heptane, was standardised using salicaldehyde phenylhydrazone as indicator. 3 Parent amines were dried by heating to 100 °C under vacuum (0.1 mbar) using a Kugelrohr apparatus for 2 h, before being purged with and stored under N 2 over 4 Ǻ molecular sieves. 1,3-Dimethyl-3,4,5,6-tetrahydro-2(1H)-pyrimidinone) (DMPU) was dried by heating to reflux over calcium hydride and distilling under vacuum before being purged with and stored under N 2 over 4 Å molecular sieves. Chlorotrimethylsilane was distilled under N 2 and stored over 4 Å molecular sieves. 4-t-Butylcyclohexanone 1a and 4-phenylcyclohexanone 1d were recrystallised twice from dry hexane at 4 °C, purged with, and stored under N 2. 4-i-Propylcyclohexanone 1b, 4-n-propylcyclohexanone 1c, and 4-(tertbutyldimethylsiloxy)cyclohexanone 1e were dried by heating to reflux over calcium chloride and distilled under vacuum before being purged with and stored under N 2 over 4 Å molecular sieves.

Mechanism and Stereocontrol in Isotactic rac-Lactide Polymerization with Copper(II) Complexes

“…All reactions were carried out using Schlenk or glovebox techniques under a nitrogen atmosphere. Cu­(OMe) 2 , 1 H -pyrrole-2,5-dicarbaldehyde, and L3 were prepared according to the literature. Solvents were dried by passage through activated aluminum oxide (MBraun SPS), deoxygenated by repeated extraction with nitrogen, and stored over molecular sieves.…”

Deciphering preferred geometries of pyridylmethylamines-based complexes: A robust strategy combining NMR, DFT and X-ray

“…11 Such compounds revealed especially valuable as catalytic systems in various synthetic organo-and metallo-promoted transformations including oxidative C-C bond formation, cycloaddition reactions, Friedel-Crafts alkylation, Henry reaction, Suzuki coupling, C-H arylation. [11][12][13][14][15][16][17][18][19][20][21][22][23][24][25] Figure 1. Pma modulation sites, transition metal and proton complexes and Zn II and Co II complexes.…”

Diiminopyrrolide Copper Complexes: Synthesis, Structures, and rac-Lactide Polymerization Activity

“…Known and new diiminopyrroles L1–L7 and iminopyrroles L9–L11 were prepared by condensation of diformyl- or monoformylpyrrole with the respective amines, using techniques described previously for L1, L2, L3, L8, and L9 (Scheme ).…”

“…All reactions were carried out using Schlenk or glovebox techniques under a nitrogen atmosphere. Cu­(O i Pr) 2, Cu­(OMe) 2 , 1 H -pyrrole-2,5-dicarbaldehyde, 1 H -pyrrole-2-methyl-5-carbaldehyde, 1 H -pyrrole-2-chloro-5-carbaldehyde, L3, L8, and L9 were prepared according to the literature. Solvents were dried by passage through activated aluminum oxide (MBraun SPS), deoxygenated by repeated extraction with nitrogen, and stored over molecular sieves.…”