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A New Aspect of Magnesium Bromide‐Promoted Enantioselective Aryl Additions of Triaryl(tetrahydrofuran)aluminum to Ketones Catalyzed by a Titanium(IV) Catalyst of trans ‐1,2‐Bis(hydroxycamphorsulfonylamino)cyclohexane
Author(s) -
Chen ChienAn,
Wu KuoHui,
Gau HanMou
Publication year - 2008
Publication title -
advanced synthesis and catalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.541
H-Index - 155
eISSN - 1615-4169
pISSN - 1615-4150
DOI - 10.1002/adsc.200800169
Subject(s) - chemistry , magnesium bromide , cyclohexane , tetrahydrofuran , catalysis , aryl , substituent , iodobenzene , titanium , enantioselective synthesis , medicinal chemistry , bromide , magnesium , organic chemistry , alkyl , solvent
A novel aspect of MgBr 2 ‐promoted asymmetric triarylaluminum‐tetrahydrofuran [AlAr 3 (THF)] additions to ketones catalyzed by a titanium catalyst of 20 mol% trans ‐1,2‐bis(hydroxycamphorsulfonylamino)cyclohexane ( 2 ) is reported. The catalytic system works excellently for aromatic ketones with either an electron‐withdrawing or an electron‐donating substituent on the aromatic ring at the 2′‐, 3′‐, or 4′‐positions, affording tertiary alcohols in excellent enantioselectivities of ≥90% ee , except for the cases of phenyl addition to 2′‐methoxyacetophenone and 4‐trimethylsilylphenyl (4‐TMSC 6 H 4 ) addition to acetopheneone.