Application of transmetallation to the synthesis of planar chiral and chiral-at-metal iridacycles
Application of transmetallation to the synthesis of planar chiral and chiral-at-metal iridacycles
Diastereoselective lithiation of (S)-2-ferrocenyl-4-(1-methylethyl)oxazoline, followed by addition of HgCl2, resulted in the formation by transmetalation of an (S,Sp)-configured mercury substituted complex. Addition to this of [Cp*IrCl2]2 and tetrabutylammonium chloride resulted in a second transmetalation reaction and formation of an (S,Sp,RIr)-configured chloride-substituted half-sandwich iridacycle as exclusively a single diastereoisomer. By reversing the lithiation diastereoselectivity by use of a deuterium blocking group, an alternative (S,Rp,SIr)-configured iridacycle was synthesized similarly. Use of (R)-Ugi’s amine as substrate in the lithiation/double transmetalation sequence gave an (R,Sp,SIr)-configured half-sandwich iridacycle, complexes of this type being previously unavailable by direct cycloiridation. Lithium to gold transmetalation was also demonstrated with the synthesis of an (S,Sp)-configured Au(I) ferrocenyloxazoline derivative. Use of the (S,Rp,SIr)-iridacycle as a catalyst for the formation of a chiral product by reductive amination with azeotropic HCO2H/NEt3 resulted in a racemate.
Arthurs, Ross A.
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Hughes, David L.
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Horton, Peter
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Coles, Simon J.
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Richards, Christopher J.
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Arthurs, Ross A.
d88e1b07-6886-422f-810c-aa293043854d
Hughes, David L.
d3b8245e-976a-47e6-8fe6-6ebcf38e2255
Horton, Peter
154c8930-bfc3-495b-ad4a-8a278d5da3a5
Coles, Simon J.
3116f58b-c30c-48cf-bdd5-397d1c1fecf8
Richards, Christopher J.
bf1ec9f1-3545-450b-b64c-2984e311dfb6
Arthurs, Ross A., Hughes, David L., Horton, Peter, Coles, Simon J. and Richards, Christopher J.
(2019)
Application of transmetallation to the synthesis of planar chiral and chiral-at-metal iridacycles.
Organometallics.
(doi:10.1021/acs.organomet.8b00905).
Abstract
Diastereoselective lithiation of (S)-2-ferrocenyl-4-(1-methylethyl)oxazoline, followed by addition of HgCl2, resulted in the formation by transmetalation of an (S,Sp)-configured mercury substituted complex. Addition to this of [Cp*IrCl2]2 and tetrabutylammonium chloride resulted in a second transmetalation reaction and formation of an (S,Sp,RIr)-configured chloride-substituted half-sandwich iridacycle as exclusively a single diastereoisomer. By reversing the lithiation diastereoselectivity by use of a deuterium blocking group, an alternative (S,Rp,SIr)-configured iridacycle was synthesized similarly. Use of (R)-Ugi’s amine as substrate in the lithiation/double transmetalation sequence gave an (R,Sp,SIr)-configured half-sandwich iridacycle, complexes of this type being previously unavailable by direct cycloiridation. Lithium to gold transmetalation was also demonstrated with the synthesis of an (S,Sp)-configured Au(I) ferrocenyloxazoline derivative. Use of the (S,Rp,SIr)-iridacycle as a catalyst for the formation of a chiral product by reductive amination with azeotropic HCO2H/NEt3 resulted in a racemate.
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e-pub ahead of print date: 18 February 2019
Identifiers
Local EPrints ID: 428805
URI: http://eprints.soton.ac.uk/id/eprint/428805
ISSN: 0276-7333
PURE UUID: 3e404e4c-b524-4286-9afa-9f710d29acba
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Date deposited: 11 Mar 2019 17:30
Last modified: 16 Mar 2024 07:39
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Author:
Ross A. Arthurs
Author:
David L. Hughes
Author:
Peter Horton
Author:
Christopher J. Richards
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