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Unifying Metal‐ and Organocatalysis for Asymmetric Oxidative Iminium Activation: A Relay Catalytic System Enabling the Combined Allylic Oxidation of Alcohols and Prolinol Ether Catalyzed Iminium Reactions
Author(s) -
Rueping Magnus,
Sundén Henrik,
Sugiono Erli
Publication year - 2012
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201102551
Subject(s) - iminium , allylic rearrangement , organocatalysis , chemistry , catalysis , combinatorial chemistry , enantioselective synthesis , organic chemistry
A multicatalytic system consisting of tetrapropylammonium perruthenate/ N ‐methylmorpholine N ‐oxide (TPAP/NMO) as oxidant, and diarylprolinol TMS‐ether as chiral amine catalyst, has been developed and applied in the efficient construction of valuable chiral molecules. The one‐pot domino reactions elaborated in the present study are based on the in situ generation of α,β‐unsaturated aldehydes from allylic alcohols and their subsequent use in various asymmetric transformations (e.g., cyclopropanation, Michael addition, Michael addition/acetalization). TPAP as a substrate‐selective redox catalyst is well tolerated by the amine catalyst and the domino reactions proceed in good yields and high enantioselectivities. The compatibility of metal and organocatalysis presented herein widens the scope of asymmetric iminium catalysis.