Asymmetric Pt(II)-catalyzed ene reactions: counterion-dependent additive and diphosphine electronic effects

[reaction: see text]. Catalysis of the glyoxylate-ene reaction by dicationic P2Pt(II) complexes is subject to anion-dependent additive effects. For [((S)-MeOBiphep)Pt](OTf)2 catalysts, acidic phenols such as 3-CF3-C6H3OH or C6F5OH provide substantial rate increases but do not affect the more active...

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Bibliographic Details
Published in:Organic letters 2001-04, Vol.3 (8), p.1233-1236
Main Authors: Koh, J H, Larsen, A O, Gagné, M R
Format: Article
Language:English
Subjects:
Anions
Ions
Ligands
Models, Chemical
Phenol - chemistry
Phosphines - chemistry
Platinum - chemistry
Online Access:Get full text
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Summary:[reaction: see text]. Catalysis of the glyoxylate-ene reaction by dicationic P2Pt(II) complexes is subject to anion-dependent additive effects. For [((S)-MeOBiphep)Pt](OTf)2 catalysts, acidic phenols such as 3-CF3-C6H3OH or C6F5OH provide substantial rate increases but do not affect the more active SbF6-based catalysts. Enantioselectivity and reactivity also increased with diphosphine basicity, with 4-t-Bu-substituted MeOBiphep ligands yielding the highest enantioselectivities.
ISSN:1523-7060
DOI:10.1021/ol015702n