Macrocyclic vs acyclic derivatives of chiral bis(oxazolines); ligand distortion and enantioselectivity of Pd(II) complexes in catalytic allylic alkylation

A nBuLi‐Mediated, Expeditious and Stereoselective Ring‐Opening Rearrangement of (Arylmethylene)cyclopropane‐1,1‐dicarboxylates

“…We established the structure of 2a by 1 H and 13 C NMR spectroscopy and HRMS. We prepared (4 E )‐1,3‐diene isomer 2a′ by the reported method5 for further confirmation of the structure of 2a . We then optimized the reaction conditions.…”

“…( E )‐Dimethyl 2‐(3‐Phenylallylidene)malonate (2a′): 5,12 Yield 1.28 g, 52 %, yellow solid, m.p. 63–64 (lit.…”

Chiral Macrocyclic Bis(oxazoline) CuI Complexes – Structure/Stereoselectivity Relationships in Catalytic Cyclopropanations

“…[20] However, the C 2 -symmetric bis(oxazoline) ligands appear to be of the highest importance, since they are synthetically readily available and in some cases also afford very high enantioselectivities. [5][6][7][8][9] A range of chiral bis(oxazoline)-metal complexes have also received a great deal of attention in various other catalytic processes such as Diels-Alder and hetero-Diels-Alder reactions, 1,3-dipolar cycloadditions, [2 + 2] photochemical cycloadditions, Mukaiyama aldol reactions and Mukaiyama-Michael addition reactions, [21][22][23][24] and allylic substitution reactions, [24,25] while Pd II complexes of chiral bis(oxazolines) have been applied in catalytic allylic alkylations. [25] A comprehensive review of C 2 -symmetric chiral bis(oxazoline) ligands in asymmetric catalysis has appeared recently.…”

Comparative Study of 1,5‐Dinitrogen Schiff Bases as Potential Ligands in Palladium‐Catalyzed Allylic Alkylation.

“…[6][7][8][9][10] Recent papers have confirmed versatility of the asymmetric allylic alkylation, Scheme 1, 6 as the synthetic procedure for enantioselective formation of C-C bond in acyclic [11][12][13][14][15] and cyclic 16 substrates, or in its intramolecular variant. 17 Despite of the large number of reports dealing with the activity and enantioselectivity of palladium catalytic systems in allylic alkylations, only a couple of studies was reported on the activity of C 1 symmetric 1,5-dinitrogen ligands.…”