In:
Chemistry – A European Journal, Wiley, Vol. 21, No. 27 ( 2015-06-26), p. 9720-9726
Abstract:
Octahedral iridium(III) complexes containing two bidentate cyclometalating 5‐ tert ‐butyl‐2‐phenylbenzoxazole ( IrO ) or 5‐ tert ‐butyl‐2‐phenylbenzothiazole ( IrS ) ligands in addition to two labile acetonitrile ligands are demonstrated to constitute a highly versatile class of asymmetric Lewis acid catalysts. These complexes feature the metal center as the exclusive source of chirality and serve as effective asymmetric catalysts (0.5–5.0 mol % catalyst loading) for a variety of reactions with α,β‐unsaturated carbonyl compounds, namely Friedel–Crafts alkylations (94–99 % ee ), Michael additions with CH‐acidic compounds (81–97 % ee ), and a variety of cycloadditions (92–99 % ee with high d.r.). Mechanistic investigations and crystal structures of an iridium‐coordinated substrates and iridium‐coordinated products are consistent with a mechanistic picture in which the α,β‐unsaturated carbonyl compounds are activated by two‐point binding (bidentate coordination) to the chiral Lewis acid.
Type of Medium:
Online Resource
ISSN:
0947-6539
,
1521-3765
DOI:
10.1002/chem.201500922
Language:
English
Publisher:
Wiley
Publication Date:
2015
detail.hit.zdb_id:
1478547-X
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