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Towards Continuous Flow, Highly Enantioselective Allylic Amination: Ligand Design, Optimization and Supporting
Author(s) -
Popa Dana,
Marcos Rocío,
Sayalero Sonia,
VidalFerran Anton,
Pericàs Miquel A.
Publication year - 2009
Publication title -
advanced synthesis and catalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.541
H-Index - 155
eISSN - 1615-4169
pISSN - 1615-4150
DOI - 10.1002/adsc.200900163
Subject(s) - amination , enantiopure drug , chemistry , allylic rearrangement , enantioselective synthesis , substituent , ligand (biochemistry) , catalysis , combinatorial chemistry , linker , organic chemistry , polymer chemistry , biochemistry , receptor , computer science , operating system
A family of enantiopure diphenylphosphinooxazolines (PHOX) containing in their structures a sterically tunable alkoxymethyl group (‐CH 2 OR) has been optimized for the palladium‐catalyzed asymmetric allylic amination. The optimal catalyst (R=CH 3 ), depicting very high catalytic activity and broad scope applicability, has been further modified to include an ω‐alkynyloxy substituent of variable length for polymer supporting via click chemistry , and has been anchored onto slightly cross‐linked azidomethyl poly(styrene). The length of a polymethylene chain connecting the PHOX unit with the 1,2,3‐triazole linker has been optimized, and the first polymer‐supported PHOX ligands for the highly enantioselective allylic amination have been prepared in this manner. Conditions for catalyst recovery and reuse in microwave‐promoted amination reactions have been established, and the system has been finally adapted to continuous flow operation.