Abstract
The formation of hetero multimetallic complex having B-O-Ti bond could increase the Lewis acidity of titanium. A novel LLA system made up of Ti-BINOL and 4-(trifluoromethyl)phenylboroxin dramatically accelerated the allylation reaction of aldehyde with high enantioselectivity.
Key words
aldehydes - allylations - asymmetric catalysis - titanium - Lewis acid assisted chiral Lewis acid catalysts
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9 A referee has argued that an ionic complex made up of borane-iso propoxide ate complex and cationic titanium(IV) triiso propoxide could be formed and act as catalyst.
10 Maruoka has reported bis [binaphthoxy(iso propoxy)tita-nium] oxide having Ti-O-Ti bond. In this paper, they assumed this type activation system (LLA) as one of the possible intermediates for the reaction. See ref.
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