Biomedical subjects
Publications and source records attributed to Moshe Portnoy.
Chiral Pybox (pyridine-2,6-bis(oxazoline)) ligands can be cleanly and efficiently prepared on polystyrene support via a five-step solid-phase synthetic sequence. Cu(I)-complexed polymer-bound Pybox was used as a catalyst in the first heterogeneously catalyzed asymmetric addition of alkynes to imines. Best enantioselectivity was observed with (t)Bu-substituted oxazolines.
A synthetic scheme for the solid-phase synthesis of unprecedented polythioether dendrons has been established, the dendrons prepared up to the fourth generation, and the applicability of the dendronized resins for supported catalysis has been demonstrated.
[reaction: see text] Phosphine-palladium complexes, immobilized on polystyrene, demonstrated a remarkable increase in catalytic activity and selectivity in the Heck reaction upon the introduction of a dendritic spacer between the support and phosphine. For some reactions an up to 5-fold increase in yield is observed.
A remarkable increase in catalytic activity and selectivity in the intramolecular Pauson-Khand reaction is observed for Co complexes, immobilised on second- and third-generation dendron-functionalized polystyrene, as compared with their analogues on non-dendronized support.
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