Synthesis and resolution of an α-phenyl substituted ortho-palladated matrix

Di-Palladium Complexes are Active Catalysts for Mono-N-Protected Amino Acid-Accelerated Enantioselective C–H Functionalization

“…22,[37][38][39][40]107 Initial rates of cyclopalladation were determined by assaying reaction aliquots quenched with (S)-N,N-dimethylamino-Lphenylalanine (Figure 10A). 18,21,108 The quenching agent halts C−H activation by sequestering unreacted palladium acetate as the bis-chelate (Figure S83). The chelating ligand also simplifies the complex ensemble of cyclopalladation products in solution, leaving two diastereomeric palladacycles (corresponding to enantiomeric products of C−H activation).…”

New principle for palladacycle resolution: diastereoselective monomer to dimer conversion

“…As the chiral derivatizing agent for transformation of enantiomers into diastereomers we have chosen (S)-prolinate, because this available optically active auxiliary ligand works very efficiently with diverse other PC- 16,17 and CN-palladacycles. 18 …”

“…To the best of our knowledge, only two properties of diastereomeric derivatives of palladacycles have been used to date for the separation of their enantiomers: a difference in the solubility of two diastereomers [15][16][17][18][19][20][21][22][23][24][25][26][27][28]47 or in their chromatographic mobility. [29][30][31][32][33] The new methodology described here is based on the difference in stability of two diastereomeric palladacycles relative to the achiral sorbent (here it is silica).…”

“…Two main approaches to enantiomerically pure palladacycles are commonly used: (i) synthesis from optically active ligands (commercially available, 1-8 pre-resolved [9][10][11][12][13] or prepared by asymmetric synthesis 14 ); and (ii) resolution of racemic cyclopalladated compounds by recrystallization [15][16][17][18][19][20][21][22][23][24][25][26][27][28] or chromatographic separation [29][30][31][32][33] of their diastereomeric derivatives. The third method based on the asymmetric activation of the C-H bond under control of an optically active base [34][35][36][37][38][39] or ligand in the palladation agent [40][41][42] is not so popular and used mainly for prochiral substrates.…”

Di-Palladium Complexes are Active Catalysts for Mono-N-Protected Amino Acid Accelerated Enantioselective C-H Functionalization

“…25,28,29,31,32,93 Initial rates of cyclopalladation were determined by quantification of reaction aliquots quenched with the (S)-N,N-dimethylamino-L-phenylalanine ( Figure 15A). 49,52,94 The quenching agent halts C-H activation by sequestering un-reacted palladium acetate as the bis-chelate (SI Figure 83). The chelating ligand also simplifies the complex ensemble of cyclopalladation products in solution, leaving two diastereomeric palladacycles (corresponding to enantiomeric products of C-H activation).…”