Catalytic Asymmetric 6π Electrocyclization: Enantioselective Synthesis of Functionalized Indolines†
Eleanor E. Maciver
Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA (UK) http://msmith.chem.ox.ac.uk
Search for more papers by this authorSam Thompson Dr.
Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA (UK) http://msmith.chem.ox.ac.uk
Search for more papers by this authorMartin D. Smith Dr.
Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA (UK) http://msmith.chem.ox.ac.uk
Search for more papers by this authorEleanor E. Maciver
Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA (UK) http://msmith.chem.ox.ac.uk
Search for more papers by this authorSam Thompson Dr.
Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA (UK) http://msmith.chem.ox.ac.uk
Search for more papers by this authorMartin D. Smith Dr.
Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA (UK) http://msmith.chem.ox.ac.uk
Search for more papers by this authorWe acknowledge funding from the Royal Society (MDS), GSK and the EPSRC (E.E.M. and S.T.), the University of Oxford John Fell Fund and AstraZeneca. We thank Dr. John Ward (GSK) and Dr. Andrew Cridland (GSK) for useful discussions, Dr. Amber Thompson for assistance with X-ray crystallography, and Prof. Ian Fleming FRS for insightful comments.
Graphical Abstract
How to close a ring: An approach to catalytic asymmetric 6π electrocyclization leads to a highly enantioselective process that was used in the synthesis of chiral indolines (see scheme). Treatment of N-aryl imines under phase transfer conditions in the presence of N-benzyl cinchonidinium chloride generates a delocalized 2-aza-pentadienyl anion system that cyclizes in up to 99 % yield and 98 % ee.
Supporting Information
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